Create a new clean skin from scratch

The current skins (dodo, finch and albatross) are too 'dirty', meaning that:

• dodo was created with very little care for accessibility, extensibility and codestyle elegance
• finch inherited dodo and mostly added new code to hide the flaws in it, making it a bit more extensible and accessible, but bloating the skin; now it contains a lot of dead style and markup
• albatross inherited finch, adding even more new markup to override dodo and finch.

So, the official skin is a complete mess, with deprecated templates, overridden templates from the /templates/ directory, useless css. This makes the skin very hard to comprehend, thus very hard to change or extend.

We should start a new skin from scratch, having not only the look in mind, but also ease of extensibility, a clean and logical structure, accessibility, ease of integration with AJAX enhancements.