documentation typo - activeBtnClass

[jasonrsavino]

Currently the Beta 2 documentation on page: http://jquerymobile.com/demos/1.0b2/docs/api/globalconfig.html states that the activeBtnClass default should be "ui-page-active" when, in fact, it should be "ui-btn-class".

I am working on a system that allows developers the access the configurable options through an admin page. I gave them "ui-page-active" as the default as per the documentation and it caused all sorts of fun things to happen.

thanks for the great work!