Changes

Adding some new code that puts the diffusion term d(wp2*em)/dz into a new function, creates a new wp3 budget term (wp3_pr_dfsn), and adds that new budget term to pyplotgen.

Adding new coefficient to control the wp3 pressure diffusion term.

Some minor updates to advance_wp2_wp3 relevant to the pr_turb and pr_dfsn terms.

Converting em*d(em)/dz to d(em^2)/dz in the wp3_pr_turb term and fixing a typo.

Renaming C_wp3_turb --> C_wp3_pr_turb (BIT_CHANGING due to name change in netcdf output).

See #884.

Resetting C_wp3_pr_dfsn constant to zero in two tunable_parameters.in files since it was set to 0.1 by mistake.

Pyplotgen update:

Adding wp3_pr_dfsn to the residual calculation in pyplotgen to get the residual line correct.

These changes add the new fourth-order moment variables wp2up2 and wp2vp2 to the CLUBB code. This requires a new function in pdf_closure_module since they must be calculated separately with a new formula, and they are fed through into advance_wp2_wp3 for use with the pr_dfsn subroutine. They are also added to the standard stats file and will be output to netcdf, hence this commit is BIT_CHANGING.

The new variables are also added to pyplotgen as part of VariableGroupWs.py where wp4 is found.

See #920.

Renaming parameter C_wp3_turb-->C_wp3_pr_turb in the alternative tunable_parameters files.

Putting the wp3_pr_turb formulation back to its d(rho*wp2*em)/dz form.  This would be a BIT_CHANGING commit since it would change the answers for the pr_turb term. However once this branch is merged into the master branch, results should be bit-for-bit since this term was only modified in the alternate branch.

See #920.

Pyplotgen updates: adding new wp3_pr_dfsn term to SAM style budgets.

See #895 and #920.

Added intent comments for the following files:
advance_clubb_core_module, advance_helper_module, and advance_windm_edsclrm_module.
These changes are BFB.
For ticket #924.