Use the term 'templates' instead of 'skins'

The term 'skins' was arbitrarily chosen. 'templates' is a better choice. We need to change the name of the skins folder, all paths that point to it, all @package skins, all Skin classes, pretty much any and every mention of 'skins' and 'evoSkin' gotta change. And the yet-to-be-written autodocs shall use the right term.