certificate PDF: fix so that it's on one page, write entire date line via text method in Prawn

- use updated PNG from Jason
- fix the generated PDF so that it's on one page.  (The auto placement of the image was pretty far off and caused the PDF to balloon into 3 pages instead.)
- rather than just paste the date on to the certificate PDF, write the entire final line to the certificate PDF via the "text" method.

TODO(?):
- update Prawn gem, make sure PDF still prints nicely
- handle long full-names properly (maybe with linewrap?)
Merge pull request #19 from nmassey/pdf-pages-fix

certificate PDF: fix so that it's on one page, write entire date line vi...
Fix security holes
Add code to show quiz results
Adding training_type to where clause
Adding training_type to where clause
adding security around editing companies
Adding description to document repository
Adding description to document repository
Adding training type to document repository
Adding code to enable different document repositories based on training types
Adding code to allow for document repositories by training_id
Adding more handling for ajax calls
Adding training_type to document_repositories list view
Adding training_type to document_repositories list view
Adding training_type to document_repositories list view
Only check that a user has completed training for their training type id
Fix incorrect order by
Fixing javascript error
hradmin's edit profile screen doesn't need to expose company