Updated documentation, made a protected field private (as it should have been long ago).
Cleaned up the registry class mess. Now there is just a single
templated class, intended to be used with pointers. You have to make
sure you do not instantiate it with a pointer type (unless you really
do want pointers to pointers, of course).
Slight behavior change: anonymous configurables are not added to registries anymore.
performing a better search in fpplib::Factor::find<SubType>
tweaks
switchable ownership of registered instances
adapt to updates in fpplib, rm deprecated method