Description

Cleaning up the vtk file read in and adding unit tests. In the future, we should rewrite the entire section of the code to avoid using IntegrationsTools.

Removing pFunction feature as it is rarely used and unwieldy to use. Instead we, can demonstrate how to add helper functions to customPDE.h that may reduce the bulkiness of equations.cc for complicated physics.

If we want to parallelize the read-in it becomes rather difficult. Essentially what we're doing is reading in the points and values and interpolating onto the some dealii:VectorTools::interpolate the same way we do for the initial conditions. This becomes challenging in parallel because the partitioning of vector we're interpolating onto may be different than whatever scheme we use.

Closes #124

Checklist

Miscellaneous items that may need to be done when making a PR:

• Documentation related to this PR is up to date (Doxygen format)
• Unit test(s)
• Code is properly formatted
• Application update script is up to date
• PR labels are applied
• Issues are linked