Allow peripherals to have multiple types (#963)

Peripherals can now have multiple types:
 - A single primary type. This is the same as the current idea of a
   type - some identifier which (mostly) uniquely identifies this kind
   of peripheral. For instance, "speaker" or "minecraft:chest".

 - 0 or more "additional" types. These are more like traits, and
   describe what other behaviour the peripheral has - is it an
   inventory? Does it supply additional peripherals (like a wired
   modem)?.

This is mostly intended for the generic peripheral system, but it might
prove useful elsewhere too - we'll have to see!

 - peripheral.getType (and modem.getTypeRemote) now returns 1 or more
   values, rather than exactly one.
 - Add a new peripheral.hasType (and modem.hasTypeRemote) function which
   determines if a peripheral has the given type (primary or
   additional).
 - Change peripheral.find and all internal peripheral methods to use
   peripheral.hasType instead.
 - Update the peripherals program to show all types

This effectively allows you to do things like
`peripheral.find("inventory")` to find all inventories.

This also rewrites the introduction to the peripheral API, hopefully
making it a little more useful.

src/main/java/dan200/computercraft/api/peripheral/IPeripheral.java

@@ -10,6 +10,8 @@ import net.minecraftforge.common.capabilities.Capability;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
+import java.util.Collections;
+import java.util.Set;
 
 /**
  * The interface that defines a peripheral.
@@ -31,6 +33,18 @@ public interface IPeripheral
     @Nonnull
     String getType();
 
+    /**
+     * Return additional types/traits associated with this object.
+     *
+     * @return A collection of additional object traits.
+     * @see PeripheralType#getAdditionalTypes()
+     */
+    @Nonnull
+    default Set<String> getAdditionalTypes()
+    {
+        return Collections.emptySet();
+    }
+
     /**
      * Is called when when a computer is attaching to the peripheral.
      *

src/main/java/dan200/computercraft/api/peripheral/PeripheralType.java

@@ -6,9 +6,13 @@
 package dan200.computercraft.api.peripheral;
 
 import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableSet;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Set;
 
 /**
  * The type of a {@link GenericPeripheral}.
@@ -18,13 +22,19 @@ import javax.annotation.Nullable;
  */
 public final class PeripheralType
 {
-    private static final PeripheralType UNTYPED = new PeripheralType( null );
+    private static final PeripheralType UNTYPED = new PeripheralType( null, Collections.emptySet() );
 
     private final String type;
+    private final Set<String> additionalTypes;
 
-    public PeripheralType( String type )
+    public PeripheralType( String type, Set<String> additionalTypes )
     {
         this.type = type;
+        this.additionalTypes = additionalTypes;
+        if( additionalTypes.contains( null ) )
+        {
+            throw new IllegalArgumentException( "All additional types must be non-null" );
+        }
     }
 
     /**
@@ -46,7 +56,55 @@ public final class PeripheralType
     public static PeripheralType ofType( @Nonnull String type )
     {
         if( Strings.isNullOrEmpty( type ) ) throw new IllegalArgumentException( "type cannot be null or empty" );
-        return new PeripheralType( type );
+        return new PeripheralType( type, Collections.emptySet() );
+    }
+
+    /**
+     * Create a new non-empty peripheral type with additional traits.
+     *
+     * @param type            The name of the type.
+     * @param additionalTypes Additional types, or "traits" of this peripheral. For instance, {@literal "inventory"}.
+     * @return The constructed peripheral type.
+     */
+    public static PeripheralType ofType( @Nonnull String type, Collection<String> additionalTypes )
+    {
+        if( Strings.isNullOrEmpty( type ) ) throw new IllegalArgumentException( "type cannot be null or empty" );
+        return new PeripheralType( type, ImmutableSet.copyOf( additionalTypes ) );
+    }
+
+    /**
+     * Create a new non-empty peripheral type with additional traits.
+     *
+     * @param type            The name of the type.
+     * @param additionalTypes Additional types, or "traits" of this peripheral. For instance, {@literal "inventory"}.
+     * @return The constructed peripheral type.
+     */
+    public static PeripheralType ofType( @Nonnull String type, @Nonnull String... additionalTypes )
+    {
+        if( Strings.isNullOrEmpty( type ) ) throw new IllegalArgumentException( "type cannot be null or empty" );
+        return new PeripheralType( type, ImmutableSet.copyOf( additionalTypes ) );
+    }
+
+    /**
+     * Create a new peripheral type with no primary type but additional traits.
+     *
+     * @param additionalTypes Additional types, or "traits" of this peripheral. For instance, {@literal "inventory"}.
+     * @return The constructed peripheral type.
+     */
+    public static PeripheralType ofAdditional( Collection<String> additionalTypes )
+    {
+        return new PeripheralType( null, ImmutableSet.copyOf( additionalTypes ) );
+    }
+
+    /**
+     * Create a new peripheral type with no primary type but additional traits.
+     *
+     * @param additionalTypes Additional types, or "traits" of this peripheral. For instance, {@literal "inventory"}.
+     * @return The constructed peripheral type.
+     */
+    public static PeripheralType ofAdditional( @Nonnull String... additionalTypes )
+    {
+        return new PeripheralType( null, ImmutableSet.copyOf( additionalTypes ) );
     }
 
     /**
@@ -59,4 +117,15 @@ public final class PeripheralType
     {
         return type;
     }
+
+    /**
+     * Get any additional types or "traits" of this peripheral. These effectively act as a standard set of interfaces
+     * a peripheral might have.
+     *
+     * @return All additional types.
+     */
+    public Set<String> getAdditionalTypes()
+    {
+        return additionalTypes;
+    }
 }