Update DOMEvent.md

'tab' was missing from possible keys list

see DOMEvent.defineKeys:
https://github.com/mootools/mootools-core/blob/master/Source/Types/DOMEvent.js#L108
Merge pull request #2568 from szegheo/patch-1

Update DOMEvent.md
Feature test for a IE legacy bug

fix sniff introduced by @cpojer in
https://github.com/kentaromiura/mootools-core/commit/103f6489c697ca0a2ec
aa33c55c8929c92359e69 for fixing one of the lots of bugs of clone node
in explorer
ensuring it will work on strict environment
Making Gruntfile.js recognize a PR and test it
Updating mouse wheel to support dom level 3 on wheel standard event

Updating mouse wheel to support dom level 3 on wheel standard event, as
per https://developer.mozilla.org/en-US/docs/Web/Reference/Events/wheel

on wheel will be used on all level 3 standard compliant browser, on
mouse wheel on the browser supporting it and DOMMouseScroll on old
Firefox
fix single quotes and using document for testing instead of creating a div
Use npm test, without explicitly install grunt-cli globally.

Stuff in `scripts` will have /node_modules/.bin added to the $PATH
https://www.npmjs.org/doc/misc/npm-scripts.html#path
Merge pull request #2572 from kentaromiura/no-sniff-1-of-3-scrollwheel

Updating mouse wheel to support dom level 3 on wheel standard event
Merge pull request #2573 from kentaromiura/no-sniff-2-of-3-oldie-clonenode-bug

Feature test for a IE legacy bug
PhantomJS is a headless browser
Merge pull request #2575 from arian/npm-test-grunt-cli

Use npm test, without explicitly install grunt-cli globally.
Merge pull request #2574 from SergioCrisostomo/travis-test-PRs

Making Gruntfile test PRs only with PhantomJS
Fixes dependencies after Karma 0.12 release
Merge pull request #2577 from SergioCrisostomo/dependencies-update

Fix dependencies after Karma 0.12 release