Progress (July-August 2013) on oauth_desktop.pl

@semifor,

I just thought I would send you a pull request in relation to my recent progress with oauth_desktop.pl.

The modifications that I have made so far are documented within https://github.com/cmlh/Net-Twitter/commits/master/examples/oauth_desktop.pl

The remaining modification to be completed are highlighted as TODO (perl) comments:
* JSON output of each tweet (added support for YAML and Data::Dumper already).
* Leverage since_id to retrieve latest tweets over time i.e. https://dev.twitter.com/docs/working-with-timelines
* If the PIN is incorrect then re-enter PIN during the initial OAuth request.
* Support Twitter API v1.1 Rate Limiting (dependency on merge of two existing Net::Twitter Pull Requests)
* Display a progress bar implementing $statuses_count minus $count
* Refactor duplicable code as sub()

Please reject this pull request if you believe these would over complicate the Net::Twitter example?