Add support for getting server info by ID + bugfix

The following comments pretty much sums it up.

Squashed commit of the following:

commit 1663c9176a804a702137ba79cc4d5438a648fcdc
Author: Samuel A. Falvo II <sam.falvo@rackspace.com>
Date:   Thu May 16 14:17:39 2013 -0700

    Refactoring and bug fix.

    Fixed a nil-dereference bug with CreateNewServer(), where if an error is
    returned for any reason, the runtime would panic as the server pointer
    is nil under those conditions.

    More poignantly, I also refactored the core logic to grab information
    about a server, given its ID, into its final resting place in the
    region.go file.

commit d4289f67df55b057af064649b13a060fdae6b91b
Author: Samuel A. Falvo II <sam.falvo@rackspace.com>
Date:   Thu May 16 13:56:13 2013 -0700

    Get Server Info functionality in example