Fix pep8 problems

Change-Id: I19c240a066ffc64ffd96b10edfa83791cd38d831
Migrate from trial to nosetests

This adds a git submodule for utilities. Now we don't need to duplicate pep8,
source-tests, and even the makefile rules.

Also, remove some not used anymore targets and async.mk which doesn't make
sense anymore and migrate from trial to nosetests.

Change-Id: I2b3f44000aae3ab30e2ef9460a4a0530f7a4f373