improve Vector<> safety checks

- make errors that will always cause a memory corruption always fatal
  (for eg: KeyedVector<>::editValue{For|At}() failure)
- make other errors fatal in debug mode, those that can be caught by
  the caller.
- fix typos

Change-Id: I65cc7d81035c37ce2906fc4500c50e5d5b5c49eb
5 files changed