Rework the main API"s that implement the calling convention. Provide utility methods to get arguments that were supplied, and provide return values. Add a VM interface to clarify the relationship between the VM, things that call the VM, and things that are called by the VM. Make the code more closely aligned with the C++ version.

src/main/java/lua/io/Closure.java

@@ -1,7 +1,7 @@
 package lua.io;
 
-import lua.CallFrame;
 import lua.StackState;
+import lua.VM;
 import lua.value.LFunction;
 import lua.value.LValue;
 
@@ -9,14 +9,18 @@ public class Closure extends LFunction {
 	public LValue env;
 	public Proto p;
 	public UpVal[] upVals;
+	
+	// TODO: change arg type to VM? 
 	public Closure(StackState state, Proto p) {
 		this.env = state._G;
 		this.p = p;
 		upVals = new UpVal[p.nups];
 	}
 
-	// perform a lua call
-	public void luaStackCall(CallFrame call, int base, int top, int nresults) {
-		call.state.stackCall( this, base, top, nresults );
+	// called by vm when there is an OP_CALL
+	// in this case, we are on the stack, 
+	// and simply need to cue the VM to treat it as a stack call
+	public void luaStackCall(VM vm) {
+		vm.stackCall();
 	}
 }