Fix Copyright year in README

Signed-off-by: Gustavo L. de M. Chaves <gnustavo@cpan.org>
Change README title

It's weird, but at
http://search.cpan.org/~gnustavo/App-GitGerrit-0.003/ the "git-gerrit"
link pointed to the README.pod HTML translation instead of to the
git-gerrit POD. I'm guessing that search.cpan.org got confused because
the ABSTRACT in git-gerrit was identical to the README title. So, I'm
changing the later to confirm in the next release.

Signed-off-by: Gustavo L. de M. Chaves <gnustavo@cpan.org>
Improve INSTALLATION instructions

Signed-off-by: Gustavo L. de M. Chaves <gnustavo@cpan.org>
Add a simple load test

Signed-off-by: Gustavo L. de M. Chaves <gnustavo@cpan.org>
Postpone Gerrit::REST requirement

Some sub-commands do not involve Gerrit at all and do not need to use
Gerrit::REST.

Signed-off-by: Gustavo L. de M. Chaves <gnustavo@cpan.org>
v0.004

  - Just a little documentation reorganization.