+ Adapted an old implementation to new syntax / commix
+ This is just a basic working version for now

+ only for tps1

- i.e. for strayField, oerstedField or magnetostaticField(=both)
- moved ComputeMaxwell to Magnetization class
- added numthreads to the test files
- added some missing import sys

+ moved all imports from top of files to functions/methods using them
+ using os.environ from within python to set environment variables for interpreter
+ use by: I = Integrator(..., numthreads=42)

+ bempp done
+ ngsolve done
+ omp not done

+ TODO: tps2(ab) not correct Je'(t) ignored

+ abstraction for compute weight in tps2
+ added C_zl and C_sl in weight computation
+ dmi axis cleaned up

moved TOL, theta, preconditionerType, guessType to parameters
set up academic test example explaining everything