[Discussion]: Consider METHOD Configure Argument ala libMesh

[pbauman]

Given all the warnings that popped out during the investigation of #582, I think we should consider mimic'ing the libMesh style of CXXFLAGS. Namely, dbg, devel, and opt. And, as in GRINS, can disable/override it if it's not wanted.

Thoughts @dmcdougall @roystgnr?