Combining consecutive cell-based simulations

Multiple calls to AbstractCellSimulation::Solve produce a collection of files named results_from_time_T where T is the start time of the simulation. These results may be combined for easier analysis or visualisation in ParaView using a simple script in the anim folder of the develop branch of Chaste.

ctest -j4 -V -R TestOffLatticeSimulation.hpp
python anim/notforrelease/MergeCellBasedResults.py $CHASTE_TEST_DIRECTORY/TestOffLatticeSimulationWithMultipleCellKillers

This will combine the result in the files results_from_time_0 and results_from_time_0.5 into a single set of results in merged_results

The script depends on the following python packages: glob, shutil, os and sys.