[WIP] Update to Mac OS X 10.10 SDK

Tested Parts
--------------

None :stuck_out_tongue_closed_eyes: 


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


Current Issues
-------

`InputHandler_MacOSX_HID::DeviceButtonToChar`

- Used the deprecated function `GetScriptManagerVariable` and `GetScriptVariable`.
    - `GetScriptVariable` is not available anymore.

---

p.s. My schedule is quite cluttered and I don't know if I can finish it or not. Please help if you can. :smile:


Whoops, I forgot to publish a commit.

Anyway, I am pretty sure that this is harmless; it will just call the fallback handler (see the line below this comment). The only annoyance may be that StepMania will always treat the keyboard as QWERTY, regardless of keyboard layout settings.

This has some implication in chat rooms and text entry screen, because the player will only be able to input in English. However, this is StepMania's current behavior on Mac OS X, because it doesn't respect my keyboard layout (I use Colemak).

Anyway, I found a replacement (indicated in the PR's comment). I just forgot to push it. Here you go, hold on!