gitian win32 upgrade to Precise 12.04

mingw upgrade fixes many bugs and possibily win64 in the future.
Rename deps .zip files to be more consistent in revision format.
Remove "msvc" compat name.
Upgrade win32 gitian to boost-1.54.0

Boost Workarounds
=================
Workaround boost-1.54.0 build bug, upstream #9156
Workaround boost-1.54.0 build bug, binary-format=pe
https://svn.boost.org/trac/boost/ticket/7262
Workaround boost build bug, upstream dev refuses to include patch to allow cross-compile.