Changes

Added non-trapezoidal zm interpolation for cloud_frac (#1127)

- Added a calculation for `cloud_frac_zm` when `l_call_pdf_closure_twice=false` and `l_trapezoidal_rule_zt=false`
This is BIT_CHANGING if `l_call_pdf_closure_twice=false` and `l_trapezoidal_rule_zt=false` since, in that case, `cloud_frac_zm` is now nonzero.
- Some minor formatting fixes
- Some minor fixes to pyplotgen's source code
- Added `a3_coef_min` to Lscale tunable_parameters.in