Add #include <locale>.  Refs #4700.

[SVN r80987]
Reduce code bloat from boost::format.  Fixes #4700.

[SVN r80989]
Fix for Ticket #7435: Crash with format using UTF16 strings on MacOS X. Reporter: Franz Detro.
https://svn.boost.org/trac/boost/ticket/7435


[SVN r83374]
Format: Remove obsolete MSVC version checks.

[SVN r86040]
Format: Remove obsolete GCC version checks.

[SVN r86110]
Merge pull request #1 from boostorg/develop

Merge to master.

All except under gcc-4.9 and the format errors are a result of Boost.Test not working correctly under 4.9.