Make CheckApi error messages more consisent and informative.

Make CheckApi error messages involving methods print out signature rather than just qualified name.
Previously, only constructor related additions and removals did this.
This made it difficult to tell which overload of a method had an API change.

Updates constructor related messages to use the fully qualified name of the class.

Also makes deprecation status change messages consistent (fields and classes now show before and after,
in addition to methods).

Change-Id: I83f06e96bf20e234fcc432ebec8d0b8ae04a22d2
3 files changed