Design and layout minor fixes
Tell if the repo is not found; prevent loading senseless page
Added ability to sign out and related layout fixes
Created mocks for several dev users
Unified calls to GitHub API to be done on server side only
Provide fully-functional dev mock to be able to work locally in dev mode

- Provided API proxy part that operates with GitHub from server side
- Provided API adapter that in case of dev mode will operate API mock
- Provided fake authentication mechanism
Humanize: message of nothing in changelog
Fixed bug that crashed update attempt
JSHint
QF misprint in No items message
QF minor layout issue on main page