Changes

Almost final loop pushes (#1012)

* Pushing loop into clip_rcm

* Pushing column loop into trapezoid routines.

* Pushing column loop into clip_covar routines.

* Pushing column loop into clip_variance and clip_skewness.

* Replacing sgn_turbulent_velocity with built in fortran sign

* Removing gr from argument list of stats calls, replacing with just nz

* Replacing some usages of gr with just the number of vertical levels

* Replacing some usages of gr with just the number of vertical levels again

* Missed a couple files to commit

* Pushing some loops and removing need for gr to be passed into some routines.

* Pushing loop into advance_xp3

* Pushing loop into mixing length

* Some more loop pushing

* Pushing some loops into mono_flux limit, skipping the lhs routine since it's a bit tricky at the moment, will do after change to grid class.

* Removing gr from argument list of stats accumulate

* Precalculating zt2zm so that we can use 2d version

* Precalculating um/vm ddzt so that we can use 2d version

* Precalculating things to use 2d version of zt2zm

* Making 2d version of cubic interp for grid class

* Small modifications to sponge damping code argument lists

* Renaming some variables

Making compatible with latest clubb change.

Making pdf_implicit_coefs_terms a type containing 2D arrays. (#1014)