Add cursor support on Elm using ecore_evas

Add cursor support on Elm using ecore_evas

Basically, get the group from widget theme, using the string passed to
elm_object_cursor_set, get hot spots x and y from the theme (keeps the object
and these two integers on cursor struct).
Cursor is set with ecore_evas_object_cursor_set()

Some functions to change style were added to the api.

SVN revision: 52760