Fix bug when saving model

I overdid it in commit #50e4263. Now,
don't reset model id in ModelActionPanelSaveHandler; only do so in
SaveModelHandler.
Delete all aliases when target component is deleted

Delete only the alias if it is selected -- don't delete the target
component or other aliases of the target.

This fixes #64.
Make "aliased" verbiage consistent

I've used "duplicated" and "linked" elsewhere. Standardize on "alias"
and "aliased".