Man pages for cms-git-tools

- Add support for MANPATH in cms-common
- Pick up cms-git-utils 0.6.4 which has initial manpages for cms git tools.
Updated to build out of git.
Actually works when building IBs.
cmssw: prepare for CMSSW_7_0_0_pre0

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>
Use version rather than revision.
Merge pull request #99 from ktf/test-version-based-cms-git-tools

Update common scripts only when major version changes.
Merge remote-tracking branch 'origin/IB/CMSSW_7_0_X/stable' into IB/CMSSW_7_0_X/devel-gcc472
Merge remote-tracking branch 'origin/IB/CMSSW_7_0_X/devel-gcc472' into IB/CMSSW_6_2_X/slc6_amd64_gcc480