update .gitignore
update Module::Install and friends
update pod
use new callback for RT 4.2 compatibility
update link
update README
update Makefile.PL
update select widget

This adds commit https://github.com/bestpractical/rt/commit/e43874c from
2010. Hints where now displayed if you use this extension.
avoid creating an extra variable
update MANIFEST and MANIFEST.SKIP