List logged-in nickname on local identities page.
Fix NPE listing local identities with expired session.

useSession() returns null if there is no valid session.
Merge branch 'session-login' of https://github.com/Thynix/plugin-WoT-staging into Thynix-session-login
Remove useless double variable initialization.
Move ID_LENGTH to where it belongs - it was a duplicate constant anyway. This also resolves a TODO.
Fix synchronization issue:
We should either not synchronize at all or synchronize over the full processing of the result set. Since we might use lazy query evaluation mode some day, I'd like to have full synchronization.
Fix identity creation not being possible when none exist
Fix hardcoding of the CreateIdentityWebInterfaceToadlet URI in LogInPage.makeCreateIdentityBox():
- fixed by providing a generic webInterface.getToadlet()
Don't generate an error message for SizeLimitExceededException here - we do not process user-entered information so this is very unlikely to happen and if it does there is no extra error message needed.
Remove l10n strings which are now incorrect since the HomePage was renamed to StatisticsPage:
I cannot update them since I don't speak those languages
Organize imports
Hide all menu entries except the "Log in" entry when no WOT identity is logged in
Use URI objects instead of String
Deny access to Toadlets by URI if there is no user logged in:
- Previously we would only hide them from the menu, which is an obvious security flaw
- Redirect the user to the Login Toadlet as a measure for denying access
- Notice that the CreateIdentityWebInterfaceToadlet is always allowed because the user needs to be able to create an identity for being able to log in
Implement a "Log out" menu entry on the web interface:
- Notice that LogOutWebInterfaceToadlet is an adapted copypasta of Freetalk. Didn't commit the original unmodified one first since the class is very small.