public class CompoundMutator
A class that collects together a group of other mutators and applies them in the order they've
been added to any script that needs modification. Any JS to be executed will be wrapped in an
"eval" block so that a meaningful return value can be created.
Mutate a script. The original, unmodified script is used to generate a script on the
StringBuilder, the "toString" method of which should be used to get the result. We make use of
a StringBuilder rather than a normal String so that we can efficiently chain mutators.