Merge branch 'stable-3.7'

Merge branch 'stable-3.7'

* stable-3.7:
  Add option --orphan for checkout
  Prepare post 3.7.0.201502031740-rc1 builds
  JGit v3.7.0.201502031740-rc1
  Support for the pre-commit hook
  Fix FileUtils.testRelativize_mixedCase which failed on Mac OS X
  Add a hook test
  Introduce hook support into the FS implementations
  If a pack isn't found on disk remove it from pack list

Conflicts:
	org.eclipse.jgit.java7.test/META-INF/MANIFEST.MF

Change-Id: I936acd24d47b911fa30ab29856094e1b2c6ac3db
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>