Some small changes to the assimilation script, include RMS error and total SMB.
Merge branch 'master' of https://github.com/douglas-brinkerhoff/VarGlaS

Conflicts:
	simulations/Greenland/balance_velocity/bv_data_assim_errors.py
Merge branch 'master' of https://github.com/douglas-brinkerhoff/VarGlaS