Added code for Licenses tab
Chenged license callback HTML
Started adding AJAX for license checking
Modified license callback function
Updated ajax for addon license checking
Added a die to the ajax
Added title for the licenses tab
Added some checks for validation to show the correct button etc
Admin sidebar content updated.
Fixed it so settings are saved if a license is valid even without hitting the 'save changes' button
Merge remote-tracking branch 'origin/licensing' into licensing
Added some messages for the validation checks. Added some basic CSS
Added spinner while ajax is processing
Updated admin message
Fixed issues with spinner
Added additional onpage check for license validity when license tab is loaded
Updated license check to show inactive message even for empty license keys
Fixed issue with deactivating message
Remove license options
Removed JS logging and commented code.