Use my stratopan address.
Switch from LWP to HTTP::Tiny.

This mean one less non-core depencency.  But it doesn't
support file:// URLs, so we have to do that ourselves.
Use StrictConstructor everywhere except Schema classes.
Update change log.
Issue a full warning when not making changes.
Fix bug when generating very large Diffs (see comments for details).

Also created helper class DifferenceEntry.