Changes

QuadTune: Adds arrow plot and plot of bias vs. a diagnostic field such as U10.

For #910.

I am making this commit because, as part of deghosting, I discovered 2
bugs in the way that COAMPS microphysics was set up.

1) The code that was handling the grid flipping for hydrometeor sedimentation
velocities output from coamps (flipping from the coamps grid to the
clubb grid) was mis-aligned;

2) The code within coamps then interpolated those velocities to the zm grid
However, CLUBB expected that output on the zt grid.

These issues were corrected in this commit that is BIT_CHANGING for
mpace_b -- the only case that uses COAMPS microphysics by default.

I am updating the snowslope output stat so it matches bit-for-bit
with the output of the clubb_ghost_exorcism branch. This commit
is BIT_CHANGING.