ENH: added new adjustment classes GageOnly and AdjustNone
ENH: added new adjustment classes GageOnly and AdjustNone

Both behave the same as the other adjustment classes, but the first only interpolates
gage observations, the second returns only the unadjusted values

FIX: fixed a bug that occurs for cross validation in two dimensions

jjhelmus/wradlib,jjhelmus/wradlib