The LX class loader parses JAR files in the LX content directory. Any
valid extension components are automatically registered with the engine as
eligible to be instantiated. Note that this requires an active, upfront definition
of all the classes contained, since any JAR file in this path is considered to
potentially hold LX content.
We subclass from URLClassLoader because the JAR files may contain more than
just class files. They may also contain bundled resource files and using this
classloader ensures that the loaded classes will get proper behavior from methods