Adding the ability for the IsolateServiceLoader to also load from the local classloader.

Basically, I've added a switch where the user can select if services can come from local or not.  It is off by default.  

In order to simplify the iterator object, I have created a `ClassLoaderSource` class with two implementations.  One is the classloader creation that already existed in the iterator - using the isolated list of jars, etc.  The other is "simple" - it just returns a classloader that is passed to it.  

In the iterator then, we start with a list of `IsolateClassLoaderSource` objects - one for each isolated jar.  Then, if loadFromLocal is turned on, we add a `SimpleClassLoaderSource` with the parent classloader at the end.  The rest of the iterator logic stays the same.