+ Migration for new RockControlGallery block.  This block won't ship with Rock, but it's handy for viewing and testing the various Rock controls.
+ Swept thru all Labled Rock Controls and made sure they all implemented ILabeledControl and also render the Bootstrap control-group/controls divs conditionally.  Now, they all will only wrap with Bootstrap control-group/controls divs if LabelText (and Help text) is non-empty