SPP's stuff
few tweaks
improved the 3source implementation
minor tweaks
carbon has its own reservoir
input only at top compartment
cleaned up fixed_compartments
tweaked parameters for nice curves

ready for adding some nitrogen source
some nice changes for nitrogen input

varied nitrate input over range 100-10000
working oxygen bubbles
added oxygen as constant term
constant methane source
constnat sources!

carbon, methane, oxygen, nitrate
intermediate workign values
in the process of tweaking variables
tweaked
cleaned up lake variables

moved to more pleasant lowercase, eliminated useless variables, and
renanmed ones that I had started to use for different purposes. started
to realign the columns in lake.m so that the tables look like tables.
fixes to calibration technique
included .txt in ingore
tweaking