do not add $MASS in shapes line if no mass is required
in case no mass is given as argument (i.e. masspoint==0) no need to search for float commas. This is not super nice from the very beginnign on. While the default is an int (0), it is replaced by a string in case agruments are given. But for the moment I will leave it as is
added option --ignore-mass-argument to give the possibility to run create-datacards.py also w/o mass argument, for exercises like the ZTT cross section estimate. In this case the datacards will still have the label ending *-125.txt to allow the other tools to work w/o problems, but signal will not be extended by a mass value during datacards creation
replaced old --stable option for the MLfit by an update as used in the HCG
Merge pull request #22 from roger-wolf/master

Making datacard setup fit for ZTT cross section estimate