Backport/PR 306 to 8.0.5 RC

Backport PR #306 to 8.0.5-RC

• Fix initial theta grid size potentially unset in call to eikcoefs

  Fixes #111

  For Miller/local and EFIT equilibria only, it was necessary to call geometry::init_theta before the call to eikcoefs, while for the remaining numerical equilibria, a call in eikcoefs to tdef was necessary after reading the equilibrium file.

  Additionally, tdef and init_theta were essentially identical, with the exception that tdef forced ntheta to be even.

  This commit will:

  • Replace tdef and init_theta with init_uniform_theta_grid

  • Always call init_uniform_theta_grid inside eikcoefs in the appropriate places

  • Make init_uniform_theta_grid private; it is now always called appropriately, so no other calls are needed

  • Replace duplicated calls to tdef with single call to init_uniform_theta_grid

  • Make the ntheta_returned out-parameter to ekicoefs no longer optional, and make it intent(inout); callers now always get the updated value

  • Add docstrings to various touched variables/procedures, making sure they are all consistent

• Make argument to init_uniform_theta_grid in-outboard

  This allows us to remove the nthg local variable, and the duplicated call to init_uniform_theta_grid for the numerical equilibria