Split up client and admin webapp

* reorganize folder layout
* split up resource / library usage
* have a common.js for both of them
* controller / views and app logic go into seperate files (admin.js, client.js)
Moved main note sync logic into service

* have a separate clientService responsible to handle REST API calls
Fix embedded resource webserver
Tweak note view and login page
Improve jshint and web client
Add notification when login fails
Lot of web client progress

* tweak login / logout behavior
* remember settings, username and permanent login
* have access tokens with different expiries in the backend
Enable CORS for web client
Implement login forms valdity check
Refactor clientService into loginService and noteService, add syncing logic
Improve note view
Improve note view, add signup form
Improve signup form

* Check if username is taken
* Use bootstrap erro/success controlls for form validation