GPU Liveness Optimization

Transformations on the Sympy equation level, that aim to reduce the amount of registers the Compiler needs. Primarily aimed at GPUs. The function livenessOptTransformation is a sequence of three sub transformations, which has been determined by a genetic optimization algorithm.
The file test_liveness_opts.py is a simple code that performs the transformation and tests whether the resulting equations are still generatable and compilable. Numerical results are not checked.