Update the power budget

[adamberenzweig]

Get better numbers for power consumption:
sleep: 0.18mA
Active: (uh, not quite sure, need to measure the average current when twinkling).
Charging:
2.13mA 0 degree full sun
1.65mA 45
0.18mA 90

there's a power budget tab on this spreadsheet:
https://spreadsheets0.google.com/spreadsheet/ccc?authkey=CL_wgeMG&hl=en_US&key=t_9UGILUetRmM7oqLXzXJgA&hl=en_US&authkey=CL_wgeMG#gid=5

The idea is to get a feel for how many hours of sun we need to balance out N hours of active cycle at night. That will help us decide how many hours to run it for, and whether we need to stagger the stars every other night or run less than 7 days a week.