Use Fody Weavers

[Cheesebaron]

Some types such as MvxCachingFragmentActivity would be nice to use Fody Weavers or similar to only have one class, but have it derive from different types of Activities.

[bspinner]

Just took a brief look on Fody - would this also clean up the copypasta I had to "implement" for the Droid Support Leanback project?

[kjeremy]

Something like Mixins might work.

[Cheesebaron]

I think we can revisit this for MvvmCross 5.x now that everything is in the same repo. Will make it easier to use weavers.

[nickrandolph]

@Cheesebaron with the consolidation in 6 is this still necessary?

[Cheesebaron]

Probably not. However, we should consider using support packages for all our Android stuff. Since that is the recommended way to go from Google either way.