Create a branch for documentation work.

svn path=/branches/doc/boost/signals.hpp; revision=44584
Initialise svnmerge.

svn path=/branches/doc/boost/last_value.hpp; revision=44600
Merge with trunk.

svn path=/branches/doc/boost/signal.hpp; revision=44810
Fix some invalid xml.

svn path=/branches/doc/libs/signals/; revision=45142
Merge latest changes from unordered.

svn path=/branches/doc/boost/signal.hpp; revision=45892
Delete the old unordered container branches.

svn path=/branches/doc/boost/signals/; revision=46609