Support for picking which columns are visible.
Adjusted demo to include new column picker
Options for column picker added to Board demo
Board Documentation updated

- added new options (for column picker)
- cleaned up existing documentation
Added options to localize labels.
Changes to SPFilterPanel demo in support of changes to a more responsive UI
Changes to better identify inputs
Changes to better identify inputs
Changes to better support a response UI
Added support for outputing any markdown errors
Adjustments to Filter panel widget demo
Cleanup of Board documentation
Support for showing a placeholder when moving items on the board.
Support for showing a button at the top of the Widget in addition to the bottom.
Update built version of plugin