Fix #346 - FA2 supervisor is now relative to a sigma instance
Adding an option to disable webworkers for FA2 layout
It is now possible to shunt the worker by specifying worker: false in FA2 configuration.
Adding possibility to run FA2 from external worker file
Fix #347 - adding a polymorphism for the autoRescale setting
It is now possible to pass an array of properties to rescale to the autoRescale setting.
Temporary dirty tricks to permit usage of sigma in node