fix issue 92

See also issue #92 (closed).

Make sure all paths are quoted in the generated cluster batch scripts (*.p files), and perform some additional sanity checks to avoid rsync-ing on paths that are obviously wrong. If users would input spaces at unexpected places this could lead to unintended side affects such as destruction of data. Mainly wetb/prepost/Simulations.py and wetb/prepost/simchunks.py are affected.