Qt4 on Mavericks (WIP)

### Description

Some API changes in Mavericks (10.9) prevent Qt4 from compiling.  This PR incorporates code that is currently undergoing review and development in the Qt code review system, and from the WebKit trac system.  Since Qt is such a widely used dependency and in many cases absolutely essential it made sense to gather the code and patch the Homebrew Qt formula to get it building again in lieu of the next upstream Qt4 release.  This formula also enables building Qt with libc++ on Mavericks (thanks @balr0g!), which is required to build a fair number of formula that in turn depend on Qt.

### Using this patch

`brew install https://raw.github.com/cliffrowley/homebrew/patched_qt/Library/Formula/qt.rb --HEAD`

### References

Incorporated Qt patches:

* [WIP: Compile on Mac OS 10.9](https://codereview.qt-project.org/#change,69328) (still WIP)
* ~~[Make QCoreWlan plugin compile on 10.9](https://codereview.qt-project.org/#change,69325)~~ (now merged into HEAD)

Incorporated WebKit patches:

* http://trac.webkit.org/changeset/107489
* http://trac.webkit.org/changeset/92556

Relevant Qt bug reports:

* [Qt 4.8.5 build failure on OSX 10.9 Mavericks](https://bugreports.qt-project.org/browse/QTBUG-32237) (Status: Reported)
* [SSSE3 fails on latest Haswell based MacBook Pro and Air](https://bugreports.qt-project.org/browse/QTBUG-34499) (Status: Need More Info)

### Haswell & SSSE3 build failure

Despite supporting SSSE3, the newer (2013) Haswell based Macs seem to have issues compiling Qt with SSSE3 optimisation switched on.  If you have one of these machines, and this formula does not compile for you then you probably saw this message:

> It appears you have a Haswell based CPU. It seems that Qt fails to build on some newer (2013) Haswell based machines.
> Try building again but adding --without-ssse3 to the end of the command line, and let us know if this worked for you.

If you have tried adding `--without-ssse3` to the command line and the build *still* fails, then add `-v` to the command line and run the build once more.  Then when it fails, find the error in your terminal buffer and add a comment to this pull request along with the output of `sysctl -a` and we'll see if we can work it out.

I've submitted a bit report with Qt regarding this issue [here](https://bugreports.qt-project.org/browse/QTBUG-34499), but it's still waiting for more info from users who have an affected machine.  I do not have one, so I cannot assist further.