Refactored driver scripts diffrisk.py etc into kamphir.py because

Rscript that specifies model is being passed as an argument.
Removed some unnecessary files from /tests folder.
Modified knorm calculation in Kamphir.evaluate() to avoid numerical
  overflow.
Fixed #8.  Parse lines individually from outfile containing Newick
  tree strings from R simulation in order to handle exceptions from
  NewickIO parsing.
Starting to implement restart functionality (restoring state from
  logfile), see #9.