Unit tests: A first approach

This is what came out from our discussion about Unit Tests. From a top-level point of view:

• We´ll go through all posible parameters with a bash-script using different .ini (We only need to check if the solver works)
• We´ll also test the basic lin-alg and methods from the vector class.

A detailed version of the things to test with the bash script:

• Test with and without LIME (@Leemhuis1, @ramirezhidalgo What would be the best way to test this? Artur Suggested to check if Matrix-Vec-Multiplication works, but we are unsure)
• Test with MPI turned ON and OFF.
• Number of Levels (1, 2, 3 / 4(?))
• Different smoothers (e.g. SAP)
• Odd-Even Preconditiong: ON and OFF.
• With or without Iterative Setup (up to 2 iters)
• Test with and Without Clover term.
• Mixed Precision: ON and OFF.

These things should be tested with the 8⁴ and 16⁴ lattices.

Any input is welcomed 😄