Merge pull request #1 from Limited-Edition/master

AvalonEdit Removed
Add changes from 2014-12-04

Added Common.Data project
Added preliminary Document handling
Added ability to translate file extention to a mimetype
Added IStorage interface
Added test project for our models
Merge pull request #2 from Limited-Edition/master

Xaml View
Add changes from 2014-12-04

Added ability to save files
Added ability to open files
Use PCLStorage for super cross platform compatible way of handling
storage