update .gitignore
update MANIFEST and MANIFEST.SKIP
update Module::Install and friends
update Makefile.PL
update pod
add Changes file
move gravatar div from gravatar element to callbacks
fix gravatar image slightly overlapping requestor name
move the HasGravatar check in the callbacks

This avoids showing an empty gravatar widget on the user pages if the user
doesn't have a gravatar.
code cleanups without functional changes
send http request only if we have an gravatar url
use d instead of default parameter
check http response for is_success
show gravatar on User Summary page in RT 4.2