[Feature]: Custom ReferenceImporter in MemberCloner

[ds5678]

A draft pull request for addressing #93

One of the major design decisions I made was to require that any custom importers inherit from CloneContextAwareReferenceImporter instead of ReferenceImporter or a hypothetical IReferenceImporter interface. I felt that this was the cleanest way to maintain correct references between cloned members.

[ds5678]

@Washi1337 thoughts?

[Washi1337]

Yes, this might be the only way that I can see for now that will ensure proper references will be used, while also allowing consumers to customize the behavior of the importer.

Side note: It may be best to not change existing constructors by adding optional parameters, but rather add constructor overloads instead. Adding optional parameters to a method / constructor is a breaking change on ABI level, forcing consumers to recompile their projects that use this feature.

Introducing breaking changes I think should only happen if we want to bump up a major version (as per semver conventions). I made this mistake once with the introduction of Utf8String, causing quite a bit of trouble among developers updating from 4.5.0 to 4.6.0 :). While I think this is a nice addition, I don't think we need to bump to 5.0.0 just yet with this.

[ds5678]

Fixed!

[Washi1337]

Sorry for the delay in response. I have added a few minor questions / comments.

[ds5678]

Should be good

[Washi1337]

LGTM! Thanks.