Wrap all remaining uses of Grgit

This allows you to build from a zip folder of CC:T. Fixes #307. Also fix
the build, woops.

build.gradle

@@ -331,6 +331,7 @@ task compressJson(dependsOn: extractAnnotationsJar) {
         if (!ok) throw new IllegalStateException("Could not check release")
     }
 }
+check.dependsOn checkRelease
 
 curseforge {
     apiKey = project.hasProperty('curseForgeApiKey') ? project.curseForgeApiKey : ''
@@ -402,7 +403,9 @@ task compressJson(dependsOn: extractAnnotationsJar) {
     token project.hasProperty('githubApiKey') ? project.githubApiKey : ''
     owner 'SquidDev-CC'
     repo 'CC-Tweaked'
-    targetCommitish { Grgit.open(dir: '.').branch.current().name }
+    try {
+        targetCommitish = Grgit.open(dir: '.').branch.current().name
+    } catch(Exception ignored) { }
 
     tagName "v${mc_version}-${mod_version}"
     releaseName "[${mc_version}] ${mod_version}"

src/test/java/dan200/computercraft/core/computer/BasicEnvironment.java

@@ -23,7 +23,7 @@
 import java.net.URL;
 
 /**
- * A very basic environment
+ * A very basic environment.
  */
 public class BasicEnvironment implements IComputerEnvironment
 {
@@ -93,7 +93,6 @@ public InputStream createResourceFile( String domain, String subPath )
         return ComputerCraft.class.getClassLoader().getResourceAsStream( "assets/" + domain + "/" + subPath );
     }
 
-
     public static IMount createMount( Class<?> klass, String path, String fallback )
     {
         File file = getContainingFile( klass );

src/test/java/dan200/computercraft/core/filesystem/FileSystemTest.java

@@ -26,6 +26,10 @@ public class FileSystemTest
 
     /**
      * Ensures writing a file truncates it.
+     *
+     * @throws FileSystemException When the file system cannot be constructed.
+     * @throws LuaException When Lua functions fail.
+     * @throws IOException When reading and writing from strings
      */
     @Test
     public void testWriteTruncates() throws FileSystemException, LuaException, IOException

src/test/java/dan200/computercraft/core/filesystem/MemoryMount.java

@@ -13,7 +13,7 @@
 import java.util.*;
 
 /**
- * Mounts in memory
+ * In-memory file mounts.
  */
 public class MemoryMount implements IWritableMount
 {