Handy macros for callbacks.
Instead of:
std::bind(func_ptr, instnace, std::placeholder::_1)
you use:
CALLBACK_1(func_ptr, instance)
And also removes more warnings from the tests
Base class displays the Menu( <- O -> )
Improved in some tests the way to create entries.
Instead of defining the tests twice: the "create" method, and the entry
in the array, it is only needed in the array (ActionsTest, SpriteTest
and Texture2DTest)