Add NME support

I now have Flambe working with an NME backend. It's using bitmaps like the Flash platform, so it may make sense to optimize the rendering further. However, everything in the Piratemark benchmark is working right now.

In order to test, you need to have a development version of NME. With that installed, you can build my version of Piratemark (http://github.com/jgranick/Piratemark) like this:

    nme test html5
    nme test mac
    nme test html5 -Duse_flambe
    nme test mac -Duse_flambe

The first two will build for NME's built-in support for HTML5 or OS X (and of course there are many other targets), while the "use_flambe" define enables the "flambe" haxelib in the project.