Branch Boost.Build for next milestone

svn path=/branches/build/Milestone_12/; revision=39599
Branch Boost.Jam for next milestone

svn path=/branches/build/Milestone_12/; revision=39600
Merge changes to branch

svn path=/branches/build/Milestone_12/; revision=39604
Merge from trunk

svn path=/branches/build/Milestone_12/; revision=39622
Merge test fixes from trunk

svn path=/branches/build/Milestone_12/; revision=39625