Bugs corrected and improvements

Folders and feeds names are correctly UTF-8 saved to DB.
Post titles and contents are correctly UTF-8 saved to DB.
Added a mouse navigator to show next and previous post just by clicking the bottom part of the page
Key 'T' to show the 'add tag dialog'.
Space scroll improved.
Unread counter disapears when 0 and appears if greater than 0 dinamically.