updates macro builds for 2.11.1
fixes run-macro-sbt builds (how did it work before?!)
Merge pull request #114 from xeno-by/master

updates macro builds for 2.11.1
Refactor scala-release-2.11.x

Determine Scala version as:
  1. $SCALA_VER_BASE$SCALA_VER_SUFFIX (if former variable is set)
  2. By parsing the tag (if HEAD is tagged as v$base$suffix)
  3. By parsing versions.properties for the base version, suffixing with -$sha-nightly

Bootstrap:
  1. Build minimal core of Scala as this version (aka locker), publish to private-repo
  2. Build modules required to bootstrap, publish to private-repo
  3. Build Scala using the previously built core and bootstrap modules, publish to private-repo
     This overwrites the minimal core on private-repo

Stage to sonatype (unless building a -nightly release):
  1. Stage this Scala build on sonatype
  2. Rebuild modules with this Scala build, and stage them on sonatype as well

The script also serializes the scala version as
`version` to the file `scalaversion.envinject`, so that it can be propagate
to the downstream job that builds the actual distribution (with a bit more jenkins magic).