Revert "Update compiler.path to correct/modern value"
Revert "Update compiler.path to correct/modern value"

This reverts commit dcb15a9b1314779cd0e7418910fd5df177be2500.

This path adjustment is for 1.6.6, which doesn't seem quite stable yet.

ex-nerd/brainwave-arduino,ex-nerd/brainwave-arduino