This eliminates the recursive makefiles for libzrtp (we still
recurse to build bnlib). Object files, library files, and
executables (including tests) are now produced in the root
directory.
Move all the GNU build files to the root directory so that we look
like a normal *NIX-centric project.
Thanks to Viktor Krikrun for an initial patch here. For this commit,
I ended up redoing the move from scratch to separate out this move
from other changes.
Travis Cross