Preliminary CSS Property Priorities

Hi all,

Thanks to some epic work and encycopledic knowledge of CSS by Chris, we now
have the standardization status for all of the 574 CSS properties in our
exhaustive list of every CSS property known to man.

I've taken a first stab at assigning priorities to them in the main
tracking sheet:
https://docs.google.com/a/chromium.org/spreadsheet/ccc?key=0AkRs-89PKiZpdE0xdm9Sb1ZvRW1ZRzMtWEdyU0Z4OEE#gid=0

Here's the guidelines I tried to apply:

   -
   - P0 - Must have right this instant: (often because they're important to
   developers based on MDN's popularity data)
   - P1 - Necessary to complete milestone
   - P2 - Normal priority. The majority of these should be done for the
   milestone to be considered finished.
   - P3 - Not necessary for milestone, should have at some point in the
   future
   - P4 - Not a priority ever

*Let me know if you see any articles that you think are too highly ranked,
and any that aren't ranked high enough.*

Meanwhile, Mike Sierra is taking a stab at making our representative CSS
article. Once he's done (and we've discussed it) then we'll work on the
guide to writing css property docs.

--Alex