build_VS2013.bat: add the SVN keyword Id.

git-svn-id: http://peerblock.googlecode.com/svn/trunk@726 d3e0e2f6-51e0-11de-b413-c5e99dc0a8e2
Update Boost to v1.56.

git-svn-id: http://peerblock.googlecode.com/svn/trunk@727 d3e0e2f6-51e0-11de-b413-c5e99dc0a8e2