Token printing

This set of changes add printing of tokens

A token is a label with a QR code, Nickname, Specialty and Superpower

GET people/1.pdf will return the token image as a PDF that can be printed on a label printer
GET people/1/print_token will print the label on the default printer connected to the server

The media to print on is select in config/initilizers/qr_code.rb
Rails.config.token_media
Current supported values:
DC03 => 29 X 90 mm address labels
DC04 => 38 X 90 mm large address labels
A4 does not currently work.
Your correct will remove.

> On 28 Nov 2014, at 1:09 pm, Andreas Thurn <notifications@github.com> wrote:
> 
> In app/controllers/people_controller.rb:
> 
> > @@ -18,13 +17,15 @@ def index
> >    # GET /people/1.json
> >    # GET /people/1.png
> >    # GET /people/1.vcf
> > +  # GET /people/1.pdf
> > +  Mime::Type.register "application/pdf", :pdf
> i don't think you need to regsiter the mime type
> 
> —
> Reply to this email directly or view it on GitHub <https://github.com/StephenSmithwick/DisasterRegistration/pull/8/files#r21015052>.
>