This commit contains a refactoring of the LDAP connection handling to enable access for all users of the HTW Berlin.

Classes:
- AccountController: Code and naming improvements, add of email for user, add i18n, add JavaDoc
- LDAPConnector: Complete refactor with configurable values, code improvements, add JavaDoc

Templates:
- All templates are refactored due to the naming refactoring of Notification

Other:
- application.sample.conf: Add default parameters for LDAP connector
- messages: Add i18n for LDAP connector and authenticate controller
CSS:
- htwplus.css: Fix to show borders only on notification elements
This commit fixes various database connection leaks, that possibly occur

Classes:
- BaseModel: Restored MappedSuperclass
- Notification: Add referenceId and referenceType instead of BaseModel reference, as BaseModel should not be an entity as we might have duplicate IDs on seperate tables which might result into problems when indexing
- NotifiationService: Use referenceId and referenceType from Notification
- Post: Put several queries into transactions to avoid connection leaks
Classes:
- Notification: Remove unnecessary import
Merge remote-tracking branch 'origin/33_ldapRefactoring' into develop

Conflicts:
	app/controllers/AccountController.java
	conf/messages
CSS:
- htwplus.css: Put margin into notification-element
Classes:
- Post: Fix parameters to be final
This commit fixes broadcast notifications.

Classes:
- AdminController: Fix that all users are notified when no user is selected
- Account: Add allTransactional()

Templates:
- createBroadcastNotification: Add text for selecting users

Other:
- message: Add i18n for intro
#26 config additions
#26 local variable within inner class needs to be final
This commit fixes update of account information via LDAP if account with email exists.

Classes:
- AccountController: Fix update of account information via LDAP if account with email exists
This commit fixes some transactional issues.
Merge branch 'develop' into 17_LandingPage

Conflicts:
	app/controllers/AccountController.java
	public/stylesheets/htwplus.css