elm_win: support trapping ecore_evas calls (aka: e17 support)

elm_win: support trapping ecore_evas calls (aka: e17 support)

Allows setting a trap in elm_win that intercepts calls to
ecore_evas. If there is a trap and the trap returns EINA_FALSE, then
the corresponding call is NOT issued. If it does not exist or returns
EINA_TRUE, then the call is executed.

Enlightenment window manager will set these traps and will call
e_border directly, allowing E17 to use Elementary! A major feature
given e_widgets painful usage.

This should also help integrating into Wayland or even debug.

SVN revision: 74156