Branching strategy for move to multiplatform

[jeremy303]

What do you guys think of this?:

1. Jeff creates a new branch multiplatform off of main.
2. David finishes up final items for Android release on main.
3. Any changes to main, Jeff rebases into multiplatform
4. When ready for release, will create a new release branch and tag. If we need to do fixes, we can do so from this branch.
5. Jeff does a final rebase into multiplatform, then can do a fast-forward merge into main and delete multiplatform.
6. Development continues on the main branch.

@gtjeffw @david-peeler