PanelList added.
Merge remote-tracking branch 'Harrigan/master'
Added group behavior to Button.
Added event.Change to toggle button.
Merge pull request #48 from mikedotalmond/master

Use isDir in in place of FileSystem.isDirectory in FilesDataSource::open
Merge pull request #44 from ProG4mr/master

PanelList added.
Accordion/PanelList update
Image not longer automatically disposes bitmap