Rename Book -> UserBook and BookProfile -> Book

Previously It is quite confusing and not intuitive to refer Book & BookProfile.
Remove Old Migrations
Update fixture data
Merge pull request #2 from 9gix/feature/rename-model

Feature/rename model
Admin for Communities
Communities Serializers & Views
change User lookup field to username
Enable pagination for search provider
API Documentation for catalog views
Refactor Permissions, Allow Admin to Modify
rename permission class
Fix invalid import
User Book Serializer
Restructure User Book API serialization format
Reservation Status in Conversation

Future consideration, move Reservation as a separate Model
Remove comments for an obvious code
Merge branch 'master' into feature/reputation
Remove Unnecessary import
Migrationscript for reputation