Update to 1.7.8

Hopefully you won't delete this PR... as it's a nicely made patch without any questionable content.

First commit: Makes the plugin maven-compatible and build against the latest 1.7.2 stuff for general compatible... this is in part to work with the Citizens dev repo: http://ci.citizensnpcs.co/job/Sentry/
Second commit: Just a quick patch to 1.7.5

Also, after you pull this, I'd recommend merging the 1.7 branch to master, as 1.7 is fairly well the official support-target MC version by now.