Version 2.2.1 release

Here are the changes...

• [Requirement] Add row editing support - merge, clean innerHTML
• [Requirement] Add cell editing support - merge, clean innerHTML
• [Requirement] String Externalize wizard: save property key name prefix in preference
• [Bug] Incorrect Table rendering in some case
• [Bug] Click on , do not move to correct position
• [Bug] Cannot insert/delete table cell in some case
• [Bug] Cell selection is wrong if select from top-right to bottom-left/bottom-left to top-right