Syntax 02

Once @nsqr has approved the cleaned-up version of the folders ./NavierStokes/ (link), ./Platform/ (link), ./ko2turb/ (link), and ./Transition/ (link) we should add these syntax tests to be run on all future changes to make sure, the basic syntax requirements are met.

@frza : I inserted the two tests we currently have (Test01: 'use ..., only: ...', and Test02: '-Wunused-variable') in a class as you requested. Let me know, if I misunderstood something. Also, @nsqr would like the -Wunused-variable as a maketest, but that is really tricky to keep track of while we have not cleaned the entire code yet. I therefore opted for this solution where we can easily add a folder every time we have a new cleaned-up folder.