Minor fixes
Update Protobuf schema

- Add required fingerprint 
- Rename uri to uuid and make required
Add fingerprint to Document in parser
Add uuid to annotations
Make FileLoader slightly more generic
Embed annotation UUID in viewer 

- Use Backbone for annotations 
- Tweaks
[WIP] Delete & Highlight of annotations

- Some design considerations still needed 
- URL routing is only client side now
- Still not happy about the setActiveAnnotations() :(
[WIP] Scroll to and delete of annotations