Add gcc-arm/bin to PATH, allowing an installed version of the GCC ARM
toolchain to be found.
Remove extraneous definition
Fix typo
Fix Makefile to find path to tools (export PATH has quirks)
Merge branch 'unstable' of github.com:payne92/bare-metal-arm into
unstable

Conflicts:
	Makefile
Using the PATH to find gcc-arm binaries
Another test for GCC tools already on the path (trying to get this to
work on all platforms)
Merge branch 'unstable' of github.com:payne92/bare-metal-arm