Minor cleanup
Remove __hash__ and __eq__ from Setting

__hash__ and __eq__ didn't serve much purpose in the Setting object. In
SettingContainer and SettingPresenterContainer, use Setting.name as a
key.
Revert "Remove __hash__ and __eq__ from Setting"

This reverts commit 7c5bef02f4392584ae9b226ba041a1ed1461d672.
Revert "Revert "Remove __hash__ and __eq__ from Setting""

This reverts commit 65b5b60fe2a7c2bbf25925c5ad9fff9ae35765ae.