Move v4 support base dir to donut to match master.

This will conflict with master but will merge nicely
after.

Master already has an API4 base lib and it's called donut
instead of base. To fix a merge conflict previously,
I allowed both libs to coexist. This collapses them back.

Change-Id: I18c15cf22c20c00d8e5780a90485f9fca4894d2f
3 files changed