Mobile device support

[gorlak]

We need support for mobile devices. To start the conversation, I think a good approach would be to:

• Move the asset processing code into a wx system tray app 'Pipeline'
• Move the file modification listener into Pipeline, use it to pump the cache
• Pipeline should serve cached asset data to client programs over the network (including the editor)
• Add support to Pipeline for caching assets for multiple platforms
• Add support to Pipeline for mobile data formats (ex. PVRTC)