Cleaned up profiles in POM

* No need to have a profile for Scala 2.9. Cleaning up this makes it easier to
build the plugin as no profile need to be passed.

* Use Scala 2.10.1-SNAPSHOT for building, since this is the Scala version used
by the IDE nightlies, and you don't want to be subject to binary incompatibilities
(keep in mind that the Scala compiler jar isn't binary compatible).

* Updated link to the Jenkins job.

I need this commit to complete #9.
Merge pull request #14 from scala-ide/issue/clean-up-scala-versions-in-pom

Cleaned up profiles in POM