New implementation for Lua tables. Does not use Vector or Hashtable, instead

uses plain Java arrays directly to keep heap allocation to a minimum.
Includes some unit tests that seem to indicate the basic operations are
correct. However, the following things are not implemented:

* Shrinking the capacity when elements are removed
* Optimal storage of each element in array vs. hash when entries are
  added out of order. A junit test case is there for this.

src/main/java/lua/value/LNumber.java

@@ -19,4 +19,9 @@ public class LNumber extends LValue {
 		return TYPE_NAME;
 	}
 
+	/**
+	 * Returns false by default for non-LNumbers, but subclasses of LNumber must
+	 * override.
+	 */
+	public abstract boolean isInteger();
 }