Socalwaterindex

This pull request is because the software has been stable for several months, given one or two bug fixes and some fashion improvement (favicon). Most of the recent changes are about documentation.

A friend of mine installed it at his place and refuses to provide any bug report or new feature request despite my repeated requests :-)

So that is what one would call "stable". Now is a good time to merge.

My long term goal is to compute the watering index from the NOAA data available on the web. I retrieved all the formulas and calculation sheets I need, I verified that the NOAA provides the necessary data (on a 5 miles grid basis). I am not sure when I will start, and that will not be a trivial change. I want to do this on a separate branch because that will be disruptive. (I will keep the current watering index services, through, because there will be a testing period during which I will just compare.)