Set full shell $PATH in emacs on Mac

OSX gui apps do not inherit full $PATH from shell, now emacs does
Added after this issue/answer:
http://stackoverflow.com/questions/19803033/emacs-flycheck-configured-syntax-checker-python-flake8-cannot-be-used
Merge branch 'master' into better_python

Conflicts:
	_packages.el
Ditch python-mode in favor of standard python mode