Added basic filtering for status updates.
Added basic filtering for status updates.

You can now edit the `conditional_status` function in `master.cfg`
to tell it which branches you should filter updates for.

	modified:   buildbot/master/master.cfg

servo/saltfs,setupminimal/saltfs,rwaweber/saltfs,setupminimal/saltfs,UK992/saltfs,UK992/saltfs,setupminimal/saltfs,UK992/saltfs,ALikhachev/saltfs,rwaweber/saltfs,ALikhachev/saltfs,servo/saltfs,rwaweber/saltfs,ALikhachev/saltfs