PDF generation
move spec for testing PDF into feature (removed fixtures. whoop!)
moved presentation methods to presenters. DRYed some of the presenter hash merging. Use relative path for pdf_forms lib
add pdftk to travis
fix to handle different implemntations of pdftk treating empty strings differently
Brings up to date with master
Some PDF work refactor.

 - Minor changes
 - Rename ClaimantPresenter > PrimaryClaimantPresenter for the above. ET1 form
   only has one claimant also.
 - Remove superfluous controller code
Merge pull request #141 from ministryofjustice/pdf-suggested-refactors

Some PDF work refactor.
Merge pull request #130 from ministryofjustice/pdf_generation

PDF generation