Add module for finding libdrm
Add libdrm to build dependencies in CMakeLists.txt
Set drm flags and libraries for build
Add missing flags, inclusions and paths for libev

I forgot to add them in a previous PR extending the build env.
Merge pull request #42 from neithernut/add-build_env-libdrm

Add build env libdrm
Added simple main loop with signal handlers
Merge pull request #48 from TheNeikos/add-basic_main_loop

Added simple main loop with signal handlers
Structure the main function