General: No need to send the current username for several functions. All necessary user information can be obtained via the UserManager.getConnectionBySocket function.

Therefore some changes we needed in some files.

Server/RightManager.js: In loadDefaultRoles, a minor change was needed in the case that an object had no role.

1.rightManager.js and 1.rightmanagerDialog.js: Introduced a readonly variable that disables non manager the possiblity to change something in the right manager.

Client/UserManager.js: Introduced a prepareRoles function that checks whether we a manager or other user is accessing the roles. If the user is no manager, then only those roles will be shown, where the current user is in.
Merge branch 'develop' of github.com:winfel/wa_knowledge_structuring into develop

Conflicts:
	source/Server/UserManager.js