Reorganize dir structure, and beatify Makefile

quirks will become a very long "quirky" part of the code. Give it its own
subdir.

Also, specify the source  files in the Makefile, not the object files.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Makefile: don't blindly remove all files with .o extension

Be more selective. Only remove object files we know for a fact we are creating.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>