Added plot.sums function

The plot.sums function converts census data like
SOD.data to plot.level summaries within a site. Should
shorten scripts.
Added script to load Cobb2012 parameter data

The loaded data now automatically calculates
competitive coefficients, so this doesn't have to
be done in the model scripts.  Make this a function
in the future.
SODModel output now always array

Added method melt.SODD to convert to data frame.
Added smart progress bar
Stochastic implementation working.  Not sure why.
for ec2