Fix warnings on non-static data member initializers (C++11 feature)

We're not formally using C++11 yet so those trigger compilation warnings
(at least with GCC 5):

./main/input_default.h:122:30: warning: non-static data member initializers only available with -std=c++11 or -std=gnu++11
  CursorShape default_shape = CURSOR_ARROW;
                              ^

Note: We may allow those eventually (especially for non-int static const),
but most of current occurrences were inconsistent with all other classes.

See also http://www.stroustrup.com/C++11FAQ.html#member-init

modules/visual_script/visual_script_property_selector.h

@@ -63,8 +63,7 @@ class VisualScriptPropertySelector : public ConfirmationDialog {
 	ObjectID script;
 	Object *instance;
 	bool virtuals_only;
-
-	bool seq_connect = false;
+	bool seq_connect;
 
 	void _item_selected();