closes#424
plnkr - change plnkr.config -> plnkr.json and change output paths and names
update jade plunkers to new 'resources/live-examples' path + minor cleanup
update gulpfile to run build-plunkers as part of build-docs.
The `Transformers.markdown` (`:markdown`) filter is deprecated. This commit updates
the entire docs project to use the `jstransformer-marked` (`:marked') filter.
Jay Traband
Ward Bell
Mithun Patel
jennyraj
Peter Bacon Darwin