Lots of bugfixes.

 * Fixed the class reference to LocalTime in LocalTime.ext
 * Fixed the problem of a duplicate extension in Main.ext
 * Clarified some methods in ExtensionRegistry
 * Removed persistent group functionality from ExtensionRegistry
 * Made methods in ExtensionRegistry use generics (makes handling
services easier)
 * Added JobbedTalkerStub which uses jobs in a specific thread to handle
the internal ListenerSet
 * Minor changes in AComputeDoJob