add doc example and functional test for DataTable Color Sorting and Filtering
added hack for IE 8 bug related to varying table heights inside an inline-block element
added more complete comment to hack for IE8 bug
fixing IE8 bug with table height flowing out of container
[loader] Add support for optional dependencies
[loader] Ignore coverage for unreachable branch
[loader] Add HISTORY entry for optional dependencies
[loader] Ignore optional dependencies without a test
[loader] Document ignoring optional dependencies without tests
[loader] Ignore undeclared optional dependencies
[loader] Fail when requiring modules with failing tests
[loader] Fix access to undefined loader instance
Merge remote-tracking branch 'upstream/dev-3.x' into optional-require
[loader] Test correct attach order of optional dependencies
[loader] Check if requires list passes tests and add optionals to it

This way _sort() has knowledge of optional requires to sort them as
dependencies
[loader] Simplify _attach test for optional dependencies
[loader] Remove error from failing dependency tests
[loader] Fix attachment order test
[loader] Document loader._canBeAttached
[dom] Move out of color-base module

Currently, the `dom-style` module depends on `color-base` module only for
falling back to calculate computed style on legacy Opera (<= 12), but the
latest Opera (15+) is almost the same Chrome (`Y.UA.webkit` returns truth
actually). Many core modules are depending the `dom-style` module, I expect
that many YUI modules and applications will benefit to faster from more
than a little by this change. I also hope that this resolves #1621.