#30 Makefile changes for osx

[Andreas Poehlmann]

This patch makes backwards compatible changes to the Makefile that simplify some building scripts for osx on continuous integration services like travis-ci.
This would be good to have for building the osx wheels for the python-seabreeze wrapper.

It adds:
- "make wordwidth=fat" for building fat binaries on osx
- "make install_name=[path]" for setting install_name in the linker flags
- "make logger=0" for disabling OOI_DEBUG