Replace put-selector with dojo/dom-* modules

Based on unit test runs, this improves performance up to 20% (specifically
in IE11; IE8 actually seems to benefit less).

Code size difference is negligible once minification and compression
come into play (and using dom-construct can actually still manage to be
smaller, when one considers that the dom-* modules are likely to already be
included in the majority of cases anyway).
Ensure that dgrid.css is explicitly loaded in all test pages

(This is preparation for further work. TODO: skin.html)
List: Replace xstyle/hasClass use with inline logic
Remove use of xstyle/css! AMD plugin

TODO: reorganize CSS
TODO: document that TouchScroll.css and dojo/resources/dnd.css will need
to be included manually where needed
TODO: other doc updates e.g. styling page
TODO: update test pages that implement skin GET parameter
Rename CSS files to Stylus and create one central CSS file
Make tree tests pass again by including dgrid.css for unit tests
Add nib/vendor and use for prefixes in base.styl