Add support for HE-AAC

The code for handling HE-AAC has been copied from Matt Gallagher's
AudioStreamer library.

https://github.com/mattgallagher/AudioStreamer/blob/master/Classes/AudioStreamer.m#L1605
Update podspec to version 0.0.5
Merge pull request #24 from gangverk/master

Add support for HE-AAC