Converted answers.
Converted Application, SuggestedEdit, Tag.
Eliminated remaining use of type IDs.
Enhancement to StacManClient.

- Switched from synchronized keyword to NSLock, partially because it
performs better and we know no exceptions will be thrown, partially
because I like it more.
- Inlined `enforeBackoff:forSeconds:` because it it is only used once
in the same context as reading from backoffs.
- Improved formatting of block.
Internalized ivars, small naming tweeks.
Switched to NSLock.  Reduced dependence on ivars.