Fix #72: Respect maven patterns for sbt plugins

[jvican]

Read discussion in #72 for context.

[jvican]

I'm testing it locally, I will report whether this fixes it.

[dwijnand]

LGTM if it works.

[jvican]

It does work. The issue is that it fails because Bintray does not allow double _ in the path:

java.lang.RuntimeException: error uploading to ch/epfl/scala/sbt-release-early_2.10_0.13/0.0.1/sbt-release-early-0.0.1.pom: {"message":"Provided artifact path does not comply with Maven's convention"}

Of course, this maven path is supported by Sonatype, since we use it and synchronize to Maven Central.

I'm writing them an email. Hope this gets fixed soon in their API. And then we can merge.

[eed3si9n]

There's now an alternative PR #141, which looks to be more complete.