Use dockable framework for GUI

[albfan]

Use a dockable framework to replace actual GUI

flexdock has a license compatible with this project (apache)
https://github.com/opencollab/flexdock

Documentation:

• http://www.javalobby.org/java/forums/t52990.html
• https://github.com/opencollab/flexdock/blob/master/docs/User%20Guide.pdf