Add Typesafe CLA to readme
Update link to sbt in readme
Fix zinc rebase implementation.

The old implementation returned None if the source file didn't
actually exist on the filesystem, and also if there was no matching
rebaser for the source file.

Since we only want to rebase files underneath the given bases, and
we don't need to support relativizing paths with ../ etc., we use an
efficient and naive prefix-matching algorithm, instead of analyzing
path segments.

Conflicts:
	src/main/scala/com/typesafe/zinc/SbtAnalysis.scala
Allow -output-relations and -output-products outside the context of compilation.

This is useful for dumping that data from existing analysis files without having
to compile (e.g., if the sources have changed, so a compile would change
the outputs).

This has turned out to be useful for debugging.
Update to scala 2.10 (for latest sbt 0.13)
Update scala 2.10 tests to 2.10.0