Add framebuffer object and monitor object

This implements the framebuffer and monitor object
Yep, in C, you have short-circuting. In this example, `drmGetCap` will be executed and the result compared agains `0` first, then `has_dumb` will be checked.
The short-circuting doesn't work, if you overloaded the operatory, which you only can do in C++.
It may, however, still be considered "bad style".