Fixed typo in "isostacy" function.
Implemented first order approximation of erosion model - no consideration for density or sediment transfer.
Tweaked debug shader to display ocean depth since now it matters.
Color on satellite shader is now also a functiton of latitude equivalent for a given altitude.
Adopted a much more intelligent satellite shader based upon elevation, temperature, precipitation, and net primary productivity.
Merge branch 'master' into gh-pages