Finished overloading operators.

Add test1.cpp that can be compiled separately to test the operator
behavior.
Added more functionality to Matrix class, but it's definitely starting
to make more sense to switch to a Vector implementation.

Added the gausstest program which uses the Matrix class and implements a
Gauss-Seidel solver for the sample problem from the Wikipedia page on
the Gauss-Seidel method.
Added functions to calculate fluxes. Problems with accessing the member
matrices...  (segmentation faults)

Will re-write Matrix class using Vectors
Updated Matrix class to use std::vector rather than double arrays.

Updated gausstest ('make gauss') to correctly use the new class.