PDF generation

- [ ] Check max sizes of PDF form fields
- [ ] Check if CRs are kept in form fields


* Used fixtures instead of factory_girl as it was a better fit in this case. I really don't advocate the use of fixtures but for PDF generation I needed an example claim with all the associations built up. factory_girl does not work that way and I'd have to add a lot of after_create hooks to build up the associations.
* Used SimpleDelegator to wrap claim and associated classes to augment them with methods for building up the PDF
* pdf_form/claim_presenter_spec contains a test that uses the fixtures to build up a full hash of the details and compares this with a yaml file containing the expected data
* Moved the form constants into FormOptions so these could be reused in the pdf_form presenters
* PDF filename is created as et1_firstname_lastname - easy to change this though. Need to check requirements
* There is no consistency in the ET1 forms field naming hence why the code is not DRYer
* There's probably more intention revealing that can be done but would be nice to get this in for now
* `claim_against_security_or_intelligence_services` seemed overly verbose so shortened to `claim_against_security_services`
* Don't really like `generated_claim` path for the PDF but other options were taken. It probably belongs in claims_controller but show is already taken by 'page'