Version 1.5.1 release

• [Requirement] Add support for selecting from end of node
• [Requirement] Allow add/edit tag lib config for free edition
• [Requirement] Add config: Spring html form tag lib
• [Bug] Cursor does not move for some case
• [Bug] Cursor move to wrong position when enable "Open editor for imported page"
• [Bug] Import page does not render in some case

The end of node detection still have some problem due to browser limitation.