Fix SimpleInhibition

SimpleInhibition looks to have been broken since [9283eb5d](https://github.com/kreft/iDynoMiCS/blob/9283eb5d7e9b34161adf49f9491870a2fcf641ba/src/simulator/reaction/kinetic/SimpleInhibition.java) when the default constructor was removed, leaving the constructor with one argument. The lack of default constructor means that XMLParser.instanceCreator cannot create the class when it is specified in the protocol file, and "Unable to create class" is written to the log.

The single argument constructor is not used anywhere, so I have removed it which allows default construction of SimpleInhibition, and fixes the problem.