Ecore_X: Add start of XResource handling for xcb backend (NB: Nowhere

Ecore_X: Add start of XResource handling for xcb backend (NB: Nowhere
near finished yet). Add working OpenGL for XCB engine.

NB: wrt Opengl...Raster, this is the env var/dlsym version you
requested this morning ;)

NB: Basically what happens is, if you know you do not ever want/use
opengl, you can export ECORE_X_NO_XLIB env variable, and ecore_x will
use pure xcb to establish it's X connection. However, if you do use
OpenGL and this env var is not exported, then ecore_x(cb) will use
XOpenDisplay to init the connection.

git-svn-id: svn+ssh://svn.enlightenment.org/var/svn/e/trunk/ecore@61724 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33