The Windows client gyp files were missing proc_maps_linux.cc for the
unittest build. Adding that revealed some build errors due to it
unconditionally including <inttypes.h>. Removing the workarounds in
breakpad_types.h (and a few other places) made that build, which means
that Visual C++ 2013 is now our minimum supported version of MSVC.
Additionally I tried building with VC++ 2015 and fixed a few warnings
(which were failing the build because we have /WX enabled) to ensure
that that builds as well.
BUG=https://code.google.com/p/google-breakpad/issues/detail?id=669R=mark@chromium.org
Review URL: https://codereview.chromium.org/1353893002 .
