In all demos and samples, set display:none style on body and show body only at the end of init code.
Fixes https://github.com/ibm-js/deliteful/issues/302.
Select.md: don't use branch for jsfiddle
Stop using dcl.after(), dcl.superCall() with attachedCallback, fixes https://github.com/ibm-js/deliteful/issues/343
List widget: promote _isCategoryRenderer(renderer) from private to public. Fixes #342
Select: just adjust private comment since delite/Selection now has a radio mode