Add plugin initialization at server start

Added the ability for a plugin to specify an initialization routine that
is only executed when the SiriProxy server is started. This provides the
plugin a mechanism to perform a task that is not required to be
performed upon every connection.
Update README.md

Changed the update example because the gemify branch is a bit out of date. Dev is more useful.
Fixed problem with newer versions of bundle that complained about insecure use of :gemcutter.
Simplify plugin init

Utilize the PluginManager to initialize routines instead of duplicating
code. Also globalized $LOG_LEVEL since it's required by PluginManager.
Dev branch merge

-Adding support for running as an alternate user (makes things more secure -- experimental)
-Adding support for alternate DNS servers (defaults to Google's DNS); this should solve lots of problems
-Fixed some messaging to make it less scary
Merge pull request #453 from kylethedude/master

Allow plugins to initialize at server startup
Updating gemspec

Adding some meta-data. Not really much of a change.
Updated runtime dependencies

Fixing things for rubygems.org
Merge remote-tracking branch 'origin/master' into dev