One cell thick periodic BCs

[mnucci32]

Issue Type (bug, feature request, other)

Bug

Description of Issue

Simulations that have periodic BCs separated by a single cell, and use a face reconstruction that requires two ghost cells will crash. This should be fixed to help out simulations using multigrid that may coarsen the grid to this state.

Steps to Reproduce Issue

Choose a faceReconstruction like thirdOrder, and run a simulation that uses periodic BCs separated by a single cell.

System Details (OS, compiler, number of processors, etc)

Ubuntu, gcc-8.2, 1