Because in most cases there aren't version-specific sources, we expect
the retrieval to fail a number of times before succeeding. This
generates a lot of noise in sbt's log, so the logs will now be shown if
and only all the versions fail.
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.