LCM: Need stk_percept for Schwarz coupling. Make it a requirement so
that a percept mesh is built.
LCM: Changed Schwarz indicator to bool.
LCM: More work on BCs for Schwarz coupling.
LCM: Initial sources for point-in-cell interpolation evaluator.
LCM: Turns out that percept mesh is not needed for Schwarz coupling
as implemented. Disable its creation in this case.