Batch of Bugfixes

-=-=-=-=-=-=-=-=-

-Fixed Export UV XForm (should work now). #923
-Fixed enforcement of limits in property editor. #919
-Fixed long-standing bug of export editings in script inheritance. #914, #859, #756
-Fixed horrible error reporting in shader language. #912
-Added kinematic collision with plane (please test well). #911
-Fixed double animation track insert when using 2D rigs. #904
-VKey updates offset parameter in sprite edition. #901
-Do not allow anymore a script to preload itself. (does not fix #899, but narrows it down)
-Avoid connection editor from overriding selected text. #897
-Fixed timer autostart. #876
-Fixed collision layers in 3D physics. #872
-Improved operators in shader #857
-Fixed ambient lighting bug #834
-Avoid editor from processing gamepad input #813
-Added not keyword #752

Please test!

tools/editor/plugins/script_editor_plugin.cpp

@@ -1443,7 +1443,7 @@ void ScriptEditor::_add_callback(Object *p_obj, const String& p_function, const
 		int pos = script->get_language()->find_function(p_function,code);
 		if (pos==-1) {
 			//does not exist
-
+			ste->get_text_edit()->deselect();
 			pos=ste->get_text_edit()->get_line_count()+2;
 			String func = script->get_language()->make_function("",p_function,p_args);
 			//code=code+func;