Adds User Model

This patch contains the following changes:
- Adds missing screenshot for VBCaptionController (fullscreen)
- Adds the parse framework SDK
- Adds parse framework dependencies
- Creates VBWindow class (singleton for the window)
- Creates VBColor class (shared class for colors, closes #12)
- Fixes pointer references in VB core classe (const pointers vs. const strings)
- Adds VBParse class for Parse SDK initialization
- Adds VBUser model (closes #17)
- Adds VBVenue stub (starts #19)
- Adds VBUser and VBVenue to prefix
Merge pull request #23 from azoff/17-user-model

User Model