Initial Makefile for linux
Better Makefiles and test dir

`make` will execute a DEBUG build and compile the tests.
`make RELEASE` will compile a RELEASE build only
`make DEBUG` will compile a DEBUG build only

In all cases, a shared lib and a static lib are produced. The tests are
always compiled against the static lib.
Verified makefile with OSX, working

Removed readlink in favor of more GNU-unspecific `pwd -P`. Still seems a
little hacky. Added some more things for the test file.
Added Error in nested makefile, renamed test