Build system cleanup

Adds a configure script to automatically detect libraries and simplifies the Makefile. 

I wasn't able to test building with libcec. The version that ships with arch attempts to define the same symbol in cectypes.h and cecc.h. It is correctly disabled in this case, at least.

I didn't touch the vgfont build system. My thinking was this would make syncing with upstream vgfont easier.

`make` now only builds pidvbip. If you want to build flvtoh264 you need to either `make all` or `make flvtoh264`.