Added gist listing and viewing

Can now view gists for yourself:

    octogit(master) earino$ octogit gists
    #3068294  Output from dancer printing a dump of request                          size:  4371     language:  Text       
    #3068269  Using LWP to mess the content type                                     size:  739      language:  Perl        
    #3061200  Using random backoff                                                   size:  669      language:  Perl       
    #3061188  Using linear backoff                                                   size:  713      language:  Perl       
    #3061120  The standard way folks handle reconnection                             size:  574      language:  Perl       
    #3033418  Benchmark for qr code creation                                         size:  1524     language:  Perl       
    #2996703  Snippet of code using Inline::C and leptonica for super duper fast     size:  3416     language:  Perl       
                    image resizing                                                                                               
    #1166495  Error installing MooseX::Declare                                       size:  12016    language:  Text  

Or you can view them for a user:     

    $ octogit gists genehack
    #3078393  Automatically run tests when a file is modified                        
       file:  gistfile1.md              size:  629    language:  Markdown   
       file:  ci.pl                     size:  300    language:  Perl       
    #3064070                                                                         size:  281      language:  Text       
    #2932445  role-less throw                                                        size:  3015     language:  Perl       
    #2888388                                                                         size:  173      language:  Perl       
    #2888336                                                                         size:  151      language:  Perl       
    #2792681                                                                         size:  2623     language:  Markdown   
    #2727704  Smallest possible Cat app that is also a quine? (after                 size:  190      language:  Perl       
       http://paste.scsys.co.uk/198326 by t0m aka @bobtfish)                                                        
    #2491657                                                                         size:  483      language:  Perl       
    #2423575  Our macro.tt file for handling inputs consistently. Requires YUI3      size:  20165    language:  None       
       grids to look proper.                                                                                        
    #394635  None                                                                   size:  404      language:  Emacs      
                                                                                                         Lisp       
    #364476  None                                                                   size:  172      language:  Perl       
    #364471  None                                                                   size:  1525     language:  Perl       
    #364217  MooseX::App::Cmd + MooseX::SimpleConfig                                size:  491      language:  Perl       
    #364203  A MooseX::App::Cmd command class written with MooseX::Declare          size:  547      language:  Perl      

Or it will launch a browser to view a single one: 

     $ octogit gists 1166495 view