Send the terminal state to the pocket computer's player

As we only send the terminal to players using the GUI, the map interface
was never updated. We now will also send the terminal state to whoever
has the computer in their inventory.

This also marks the terminal as dirty when a new player picks the pocket
computer up, hopefully preventing any desync issues which might occur
then.

Fixes #42.

src/main/java/dan200/computercraft/shared/common/ServerTerminal.java

@@ -54,6 +54,11 @@ public class ServerTerminal implements ITerminal
         }
     }
 
+    protected void markTerminalChanged()
+    {
+        m_terminalChanged = true;
+    }
+
     public void update()
     {
         m_terminalChangedLastFrame = m_terminalChanged || (m_terminal != null && m_terminal.getChanged());