Link Foundation/CoreServices into unit tests so they build with DISABLE_WX.
Make check-includes.py properly report bad UTF-8 on all platforms rather than crashing on Python 3.

Doesn't really belong there, but just removing the check doesn't feel
like a good idea.
Fix UCodes.cpp to use UTF-8 encoding.
Don't murder the default PATH and CMAKE_SYSTEM_PREFIX_PATH on OS X.  Just prioritize /usr.

Changing PATH basically screws everything up, and while the attempt to
avoid MacPorts copies of system libraries was well-intentioned, it made
the OS X buildbot unable to pick up ffmpeg and libusb.

It's sufficient to put /usr first to make sure we use the system copies
of duplicated libraries.
Merge pull request #1543 from comex/utf8-issues

stupid utf-8 stuff
Merge pull request #1435 from comex/osx-build

OS X CMake improvements