empty __init__.py; ignore .pyc files
Minor tweak on sigma for PriorFactor to improve accuracy

sigma for PriorFactor should be sqrt of player's skill squared and
gamma (dynamic factor) squared. See paper (Herbrich et al., first para
on page 3.), and also Heungsub Lee's version
(https://github.com/sublee/trueskill/).

Mu, Sigma then match the values from Microsoft's webpage.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	.gitignore