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
Workaround boost-1.54.0 build bug, upstream #9156
Workaround boost-1.54.0 build bug, binary-format=pe