Fixes styleguide generator and harp compile output

 * Fixes template for v0.4.0 of the styleguide generator
 * Moves the styleguide.md file into public/ where it should have been
 * Improves npm run scripts
 * Fixed missing Overview link

"npm run styleguide" will properly build the styleguide again.
"harp compile" will continue to build the static version to www/
"npm run compile" is a shortcut to do both.

Bug=XWALK-2704
Merge branch 'kennethormandy-XWALK-2704'