Merge pull request #5 from sdague/master

add tempest.json
Add heat.json
Merge pull request #6 from hardys/heat_stats

Add heat.json
Add -a/--all for getting stats across all known projects.
Add count of reviewers in the output.
Rename stats.py to reviewers.py
Add a README.
Split some code out of reviewers.py.

Split some code out of reviewers.py that I'd like to use in another
script.
Add a script to get number and age of open reviews.