Use whatever perl we're running with

This is useful when running this script outside the production
environment.  Inside production, the current perl should always be
correct.
Updates for RT 4

Mostly simple renaming.  Also adds the "standalone" web handler since
that is useful for local testing.
Ensure .pm, .pl, .t, .diff, .patch attachments all display reasonably

Regardless of whatever content-type the client sent.
Provide a sanity check of Perl and RT paths unless --batch is specified
Pull the RT root from the environment or passed option
Save a git checkout step by specifying the branch we want to git clone
Mark pull-live executable
CPAN2RT must be used from the deploy branch

The master branch contains a reworking that tries to fix some problems,
but it hasn't been tested.
Clean up temp directories on exit

The option was misspelled.
Install RT from the latest release, not from git

We much prefer to track actual releases.  Tracking the stable trunk was
a bad habit.
Tidy up script output while installing plugins
Pull the rt4 branches for a number of extensions

This should be reverted as soon as those branches hit master in their
respective repos.