forking off old version with cumsum
using BETA as running total of battery charge, and Beta as per-timestep charge/discharge. the battery is still leaving a lot of juice on the table.
Merge branch 'master' of https://github.com/forresti/ee249_lab2
removed battery cap -- works well. (mehdi's idea). starting at a batteryMin that I've defined, and staying above that min
batt