Add support for non-URLClassloaders to LoadService (Fixes #304)

Problem

When the classloader is not a URLClassloader, it is not searched for
resources by ClassPath.  This causes discovery of services from
LoadService to render an incomplete list.

Solution

Merge the existing list of services found with ClassPath with a plain
old classloader.getResources().  Not the most pretty but it handles
cases where the classloader does not inherit from URLClassloader.

Result

Expected services are returned.