Improve submit by adding some stats and beautify diff

• Print out the summary of changes directly from running "upload"
• Add a summary to the diff output
• Make diff output a bit simpler to read

Specifically:

deqp_submit.py upload now prints changes stat at the end of a run, e.g.

Change stats:
    Fail -> Pass:4
    Incomplete -> Pass:7
    Pass -> Fail:1

deqp_submit.py diff does no longer go through a git commit git diff git reset cycle, the output is simplified to make it more readable, i.e. it is now

 testname oldState -> newState

When printed to a terminal the output is colored, and when piping, e.g. to grep the color escape codes are not printed to make grep work properly. To filter the result for the current changed outcome (e.g. Pass)

deqp_submit.py diff .... | grep Pass$