Added DataTable Keyboard Navigation module and tests.

Conflicts:
	src/datatable/build.json
	src/datatable/meta/datatable.json
Changed dependencies based on YUI  Module Explorer.
Added tests for nested table headers
Added missing dependency.
Build regular expression to extract column key via getClassName.
Made _keyMoveColTop work with nested headers.

Conflicts:
	src/datatable/js/keynav.js
Added test for PageUp on nested headers.
Changed keyActions from attribute to property.
Added setter for the focusedCell attribute.
Added keyIntoHeaders attribute to determine whether to
navigate into the headers.
Dropped the default call to preventDefault on any recognized
key.  Now, each function/listener must call it, if required.

Conflicts:
	src/datatable/js/keynav.js
Added user guide documentation for datatable-keynav.
Added tests to navigate into headers or not.
Changed the tests that use keyActions since it is now a property.
Dropped the 'groups' YUI configuration entry.
Corrected the API docs and user guide to state that use of
KEY_NAMES aliases is mandatory.
Expanded KEY_NAMES table.
Added history.md entry
key actions can now be specified with keycodes or alias

Before, it an alias was available it had to be specified,
now, either can be used.
Fixed a few jshint errors in the tests
Changed tests to work in IE

The code itself worked, what didn't work was the test.
It turns out that document.activeElement is not reliable in IE
and the tests used that a lot.  So, after trying lots of different
ways I asked in the IRC channel and @lsmith gave me the solution.

Conflicts:
	src/datatable/js/keynav.js
Update history entry.
Merge branch 'dev-3.x' of https://github.com/yui/yui3 into dt-nav

Conflicts:
	src/datatable/HISTORY.md
Merge branch 'dev-3.x' of https://github.com/yui/yui3 into dt-nav

Conflicts:
	src/datatable/docs/index.mustache
Fix a few navigation issues in the header.
Unit tests for adjustments and higher coverage score.