Rename some files
(GL) Style nits
(GL) Style nits pt. 2
Merge pull request #1075 from lakkatv/lakka

(Lakka) Fix label display with video_threaded
(GL) Turn set_texture_coords into macro
Move shader files to gfx/shader/
(GL/Gfx) Cleanup
Move gl_wrap_type_to_enum to gfx/gl.c
(py_state.c) Indenting - style nits
Move get_alignment inlined function to gfx/gl.c
(GL) gl_common.h - get rid of some macros
(GL) Get rid of context_destroy_func macro
(GL) Some further cleanups
(GL) Cleanup gl_shader_set_coords
(GL) Grab pointer to shader first
(GL) Pass shader pointer to gl_frame_fbo
Create shader_null.c and make shader_backend less dependent
on GL
Get rid of header dependencies on GL in shader_common.h
(menu_shader.c) Fix dependency on shaders being there
(GX) Build fix