Adding more notes about CUDA.
Bringing in Hemi@76a54c5af from https://github.com/harrism/hemi
Adding Stopwatch class for fine-grained kernel timing.
Hemi-ifying Device class.
Hemi...

Conflicts:
	simulator/Makefile
Changing hello.cu to test out Hemi.

Conflicts:
	simulator/Makefile
Re-arranging things a bit for hygiene.
Adding specific test-case code for Hemi.