Matrix Storage Revamp.

Letting go of the Fortran array conventions
  * shifting back to 0-based array indexing
  * shifting back to row-major order

Add the [] operator to Matrix. [0] is upper left. Incrementing indexes move
right, then wrap from right margin to left margin next row. [Nr*Nc-1] is the
lower right corner of the matrix.

Also does something useful with header guards. I like the idea of being able
to have a defined way to get the version strings of the headers I include
and separately the version strings of the headers that were used to prepare
the library to which I linked.

Nope, no tickets for any of this. Just tinkering.