Doc updates including changes related to Stateful API changes, fixes #239
use absolute MID for global.css, fixes #242
forgot to check in DialogUnderlay less files
Fix for gh-pages build error.
cleanup of register doc
general documentation about widgets
reference doc for delite/CustomElement
prepare for 0.1.9 tag
Make loading page level CSS opt-in, fixes #243.

Moved CSS like .d-popup to common.css.  Page level CSS (for body color, font etc.)
remains in global.css but global.css is no longer loaded by default.
Common.css is loaded by default instead.
prepare for 0.1.10 tag
remove extraneous semicolon in generated code
Simplify KeyNav test file.
dojo/query no longer needed, and dojo/dom wasn't being used.
Change template function's return value, to allow for future expansion.
FormValueWidget: don't fire change event unless user actually changes the value.

This is for the corner case when the user (for example) drags the slider handle
but drags it back to its original position before mouseup.

This handles the case when the widget value was set programatically sometime after
startup(), and also the case when the value is computed asynchronously after the startup()
call.

Also moved the genHandler() function to the top, just because I like defining functions
before using them.

Refs ibm-js/deliteful#199, refs #223, fixes #246.
fix jshint errors, refs #246.
Standardize which properties CustomElement.observe() reports,
regardless of whether or not browser natively supports Object.observe().

Also may inadvertently fix a bug with CustomElement#_getProps()
returning a list with duplicate entries.

Refs ibm-js/decor#17, ibm-js/decor#22, and depends on
ibm-js/decor@ae66259f04bf7e665c6666ce8ff78c058837b4ff.
architecture doc
document a11y and a11yclick
document BackgroundIframe
Container doc