Make sure the ide build has enough memory

This comes up when running the build locally.
Better not to depend on jenkins variables, anyway.
Repo HEADs to integrate depend on Scala version
Copy versions.properties to scala/ when it exists

This file captures the scala binary version being used
to (e.g.) resolve dependencies. We read it to do selective rewiring.
Rewire module dependencies using SCALA_BINARY_VERSION (if set)