Major upgrade

- Recoded prog to avoid run time limit on kernels by splitting the main
loop into several smaller parts each consisting of samples number of
iterations
- Periodic variable folding is now done by the separate global kernel
- Transient effects are now excluded outside of the main kernel
- Drastically simplified calculation of the deterministic part of
dynamics
- New programs: dich.cu and poisson.cu which are fully optimized for the
case of epl and physletta, respectively
- Scripts for benchmarking