Warned of the conflict w/ `scalacOptions := ...` in the README

I see instructions to add the sonatype release repo in all kinds of projects, but that repo is [synced to maven central](http://central.sonatype.org/pages/ossrh-guide.html#accessing-repositories), so I'm not sure of the point. Unless things show up there a few hours before central?
I can blow away my ivy cache and test w/ an older version of SBT, just to be sure...