Create README.md.
Set scalaBinaryVersion to scalaVersion
sbt 0.13.0-RC5
Move SBTRunner to its own file.
Build fixes; license; groupId = org.scala-lang.modules

The license is a standard 3-clause BSD license.

We're publishing modules under org.scala-lang.modules.
This signals they are "just another Scala library":
  - cross-versioned (cross-versioning under org.scala-lang confuses sbt)
  - backward binary compatible (but not forward like the core)

Compile under Optimize/Deprecation/Features/Lint.
bump version to 1.0-RC3
Newer scala-library fixed cmd line parsers