wicked_pdf_rails_2 0.7.9.1

This is a fork of the wicked_pdf gem which allows Rails < 2.3.4 to run. Basically no really big changes, so I am leaving most of this the same, and hopefully it will be pulled into the master. Wicked PDF uses the shell utility wkhtmltopdf to serve a PDF file to a user from HTML. In other words, rather than dealing with a PDF generation DSL of some sort, you simply write an HTML view as you would normally, and let Wicked take care of the hard stuff.