+ creating a branch for a xpressive extension that allows nesting
of regular expressions


[SVN r38759]
* Addition of a compiler for nested dynamic regular expressions. 


[SVN r38761]
oops they should be public.. 


[SVN r38763]
* due to references to other regexes, this may not be copyable


[SVN r38805]
* adding regex_id and name lookup functions. 


[SVN r39152]
Boost.Log merged to trunk.

[SVN r83860]