Add blacklist for locales  (#309)

This is for issue #309. I added here the changes for the pulse script and also the blacklist for staging beta and release, for testing. So as discussed, the blacklist will have priority when there are both.
I would change how we define blacklists and whitelists in the config file. Probably `locales_blacklist` and `locales_whitelist`? Or a `locales` property with black and white list underneath?