Added missing implementation for a few functions.

I added GetDataFilePath which is based on FHS. You can use OBS_DATA_PATH to override the hardcoded values.
I also added an implementation for GetMonitors which uses XCB, not Xlib.
I tested the "make install" process to make sure the file layout was correct in ${prefix}/share.
The appropriate changes to make the above possible were made accordingly in the autoconf files.
I'm moving away from xcb. We won't be able to take advantage of it for the most part anyways.

What little we can, can be taken advantage of from using the XCB wrapper over Xlib.
Plus, XCB seems quite a bit more complicated. I see no real reason to add that complication.
Fixed autotools to work with changes, fix code to actually compile.
Add stub file for GLX implementation for OpenGL.
Added more data pathing implementations for Linux/FHS
Added context creation implementation.

The program will currently segfault since various functions are still only stubs.
I've implementated platform_create_device and gl_create_windowinfo.
Minor change to remove redundancy
Minor cleanups.
Added platform cleanup implemenation
Finished GLX implementation
Fixed typo
Fix typo
A few bug fixes in the GLX implementation.

Really, doesn't doesn't change anything as the same config is generated.
However, the context profile will now be 3.2 due to a bug in GLX...
Minor change
Merge upstream