perlcritic

We now have 80+ Perl files in our tree, and it's growing. Some of those
files were originally written for Perl 4, and the coding styles and
quality are quite, uh, divergent. So I figured it's time to clean up
that code a bit. I ran perlcritic over the tree and cleaned up all the
warnings at level 5 (the default, least severe).

Testing guidelines:

- Many files are part of the regular build or test process.

- msvc files need to be tested separately. I tested as best as I could
on a non-Windows system.

- There are a couple of one-offs in contrib and src/test that need to be
run manually.

- The stuff under utils/mb/Unicode/ has a makefile that is not part of
the normal build process. I'll send in a few more patches to that in a
separate message that should help testing.

To install perlcritic, run

cpan -i Perl::Critic

and then run

perlcritic .

at the top of the tree (or a subdirectory).