This commit introduces a mechanism that allows sbt to find the most
specific version of the compiler interface sources that exists using
Ivy.
For instance, when asked for a compiler interface for Scala 2.11.8-M2,
sbt will look for sources for:
- 2.11.8-M2 ;
- 2.11.8 ;
- 2.11 ;
- the default sources.
This commit also modifies the build definition by removing the
precompiled projects and configuring the compiler-interface project so
that it publishes its source artifacts in a Maven-friendly format.