ENYO-3082: added option so tab switch request is fired before actual switch...

... this let the user delay the tab switch until the new panel is actually
ready. This is required to fix ENYO-3082 on Ares.
ENYO-3802: fixed doc
ENYO-3802: Immediately re-raise tab when clicking on already selected tab
ENYO-3802: declare the TebItem event handler within the component list...

... and remove a dead event handler
ENYO-3802: make event names more consistent
ENYO-3802: added sample for tab bar with call-back
Merge pull request #185 from enyojs/ENYO-3802

ENYO-3082: added option to delay tab switch

Reviewed-By: Ben Combee (ben.combee@lge.com)
Update version to 2.3.1-pre.1

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@lge.com)
Update LESS to ensure scripts tags aren't visible

Our CSS rules that affect the display property of all children have
the side effect of making the content of script tags visible.
Per the conversation at
http://forums.enyojs.com/discussion/1882/mathjax-rendering-on-onyx-buttons-and-picker-s,
this is a problem when using MathJax with Onyx, as it relies on inserting
hidden script tags with MathML content into the DOM.

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@lge.com)
Merge pull request #186 from enyojs/fix-mathjax-rendering

Update LESS to ensure scripts tags aren't visible
Update version string to 2.3.0-rc.3