Fix "logged in as" message in comment block

 - Add period between "Logged in as X" and "Log out?" messages.

 - Remove unnecessary space character.
Fix "You may use HTML" message in comments block

Add a colon after "You may use these HTML tags and attributes".
Caution: This requires the regeneration of the POT file and update of all
locales!
Merge pull request #103 from polnoft/develop

Fix messages in comment block