Option parsing through SelectionOptionManager.

Option parsing through SelectionOptionManager.

Make the rest of interaction between selection option implementation and
SelectionCollection go through SelectionOptionManager, i.e., make
SelectionOptionStorage::convertValue() call a method in
SelectionOptionManager instead of exposing the SelectionCollection
directly.  Cleans up the design a bit.  Also some include clean-up.

Change-Id: I60208a6de4c0f1dd5f89e7728f1e4ce4663c8c7b