CCAPS - avoid overspecification of boundaries

[JOThurgood]

The need to have vface bcs is just related to applying minmod at the very edge, otherwise the two ghosts for the sln vars should be enough to directly give you everything you need for the edge vars.

Add handling of the extreme case to minmod (just revert to a simple gradient there), and then change some of the loop sizes to capture the limits appropriately.

If you run with appropriate compiler flags, should check if OOB for you.

The simplification of boundary conditions should remove a number of possible sources of error/bugs and make the code easier to use.

[JOThurgood]

Are they actually over-specified?