Made HttpLoader asynchronous in NME by switching from haxe.Http to
flash.net.URLLoader (which uses curl under the hood). This means that a Http
instance passed to the constructor will be ignored, and might internal
implementation of Loader subclasses.

The URLLoader is public, for now, so that clients have access to NME specific
things like cookies.
Switch @IgnoreCover to @:IgnoreCover
Merge branch 'master' into http-loader-nme
Merge branch 'master' into http-loader-nme
Merge pull request #3 from massiveinteractive/http-loader-nme

Adds async http loading support to NME
Merge branch 'refs/heads/master' into httploader-nme-fixes

Conflicts:
	src/mloader/HttpLoader.hx