Replace tree_expand_hidden.html with Intern unit test

This tests expansion of a parent row in a tree grid when it is not in
document flow.  Prior to 0.3.1, the children would expand but be rendered
with 0 height in browsers supporting CSS transitions.
Fix tree expand tests to fail when they should
Add RTL feature-detect to fix behavior in recent Chrome versions

WebKit used to universally keep scrollbars on the right side in RTL mode,
but Chrome now swaps the scrollbar to the left side like other browsers.
Safari (6, at least) still leaves it on the right.
CHANGES.md: Note RTL alignment fix
Update version of Dojo referenced in README
Update version for tag
Update version for dev towards next release
Fix #886: Add ColumnHider trigger node to domNode to always be visible

dgrid 0.3.14 introduced a regression where the trigger node to open the menu
would no longer appear on browsers with no/hidden scrollbars.  This resolves it
by adding the node as a direct child of the grid's domNode instead, so it is
always visible regardless.

Added support for an rtl query parameter to the ColumnHider test page.

Thanks @treasonx for the initial investigation on this.
Fix handling of RTL scrollbar behavior for IE11+
CHANGES.md: Note ColumnHider regression fix
Add Dijit TextBox editor tests to dgrid/editor functional test suite