[WIP] Update to Mac OS X 10.9 SDK

Untested Parts
--------------

`ArchHooks_MacOSX::DumpDebugInfo()`

- Used `sysctlbyname` to find the Mac OS X version instead of the deprecated `Gestalt`.
    - http://stackoverflow.com/questions/11072804/how-do-i-determine-the-os-version-at-runtime-in-os-x-or-ios-without-using-gesta

`MemoryCardDriverThreaded_MacOSX::Unmount( UsbStorageDevice *pDevice )`

- Updated to use `sync_volume_np` instead of deprecated `PBFlushVolSync`.
    - http://lists.apple.com/archives/carbon-dev/2010/Nov/msg00030.html
Update metrics to prevent in-game warnings.
add TFG to repo, update date on bottom of Lua.xml
quickly disable broken continue screen
gonna tag beta 4 after this unless someone speaks up
Disable HeartEntry by default
HeartEntry works, my bad.
update sm5_beginner.txt with the content from the google doc
Changelog updated.
StepMania 5 beta 4, for real this time.
add missing 2d character metrics
I'm surprised people still use them, really
add missing 2d character metrics
I'm surprised people still use them, really
Merge branch 'master' of github.com:stepmania/stepmania
Added ScreenHeartEntry example.
Fix error that comes from using LoadFont
Merge branch 'master' of github.com:stepmania/stepmania
This file also uses LoadFont("Common","Normal"), which will cause StepMania to cry
our issue tracker moved to github a long time ago, even if we don't currently use this item.
Preserve Steps of unknown Style.
add sm5_beginner.txt to NSIS install script
Song cache version bump.