* refactor configure.ac to have distinct sections to configure each
subsystem.
* Dedicated LUMIERA_<subsys>_CFLAGS|_LIBS vars
* Fix Makefile.am's to use them, remove unnecessary dependencies
Stray dependencies to be refacored:
* tests/Makefile.am has dependencies on proc and backend
- should be moved to tests/library/Makefile.am etc anyways
* tests/lib/Makefile.am has dependency on GUI left
* src/tool/Makefile.am links GUI stuff generally, thats ok
* one threading test is broken, we don't care, merging new threadpool in
next.
