New unification build

Uber-build for releases, nightly build, scala pr validation, scala pr rebuild...
The script take a file as config, to be able to save and tag the different versions.
A number of small fixes that were required to successfully build rc2 on OSX

(cherry picked from commit e71818ad4056c42022317520c61093028d86ffab)
The actual configuration used to build RC2

(cherry picked from commit 8c11f1cb45354f215713d5c0f7d0fc776f3a50b4)
Merge branch 'wip/unification'

New uber build script