Updates

- Removed \Sparklr Library\, since it's already in the submodule
- Changed project to reference submodule instead of copied code
- Updated submodule
- Changed MainViewModel for network-support
- Changed MainPage to utilize a more MVVM-like approach
- Added PostViewModel (functionality is still basic at best)
- Added StreamPageViewModel which represents a stream with posts
- Added functionality to load the default networks with the default
number of posts