Trivial UI for compositions
Adding features to UI.

- Added login/logout REST endpoints.
- Added comments/votes/login in basiv UI
Changing organization for angular js code. Brought everything in one place. Gave structure to the code.
Adding reader page and composition page.
Refactored some Angular code to split the Home template.
Merge branch 'master' into UI

Bringing in some fix required for UI.
Adding slug in the routes.
Added support for voting and commenting on reader and composition page.
Added upload, edit and delete functinality for composition on data binding layer.
Fix page reload after edit.
User auth implementation.

- Login/Logout functionality with login modal.
- Include interceptor to check for 401 requests.
- Update the voting/commenting functinality with login check.
- Fix Login button not getting updated in the navbar.
Added basic showcase link for user.

- Added filter backend to compositions.
Minor UI fix for User showcase.
Include collections
Clean voting/commenting/collection on composition page.

- All the action protected by authentication.
- Changes in UI reflected.
Collection on reader page.

- Add collection as a nested state to 'showcase'.
- Added a root controller.
- Refined the compositions model to remove redundant fields.
Implement follow feature.
Fix follow in case of no-follow.
Add user registration

- Introduce ui-utils for form validation.
- Push all the security related API call to user artifact.
Removing DB file from the code base.