hopefully improved vorbudget by quite a bit. bottom friction contribution is now corrected using bottom vorticity instead of depth averaged rel. vor. The latter is an approximation to the bottom vorticity commonly made in barotropic / layered models
corrected bfric term in vorbudget to calculate area integral. I do a volume integral technically but the z-dimension should cancel out in numerator and denominator so effectively, an area-average. Also, corrected for bottom friction acting only where depth of integration = depth of water column