Added DocumentCount class
Enabled document counting & updated the PDF

Added the checklist to the PDF form
Move strikes location page down

The strikes used to be on page 2, but since the checklist PDF was added
to the front of the form, they've now moved to page 3.
Workaround for when the attributes are present

In some cases an attribute is present but all it contains is the
newline. This is a workaround not create an extra count when it isn't
required.
Renamed one of the fields in PDF, added tests

Renamed 'number-copies' to 'copy_number' so that it can be used as a key
in Ruby hash (the hyphen was the issue).

Modified the test so that they check for the correct value of
'copy_number'.
Updated the page number references

On confirmation page, the numbers have been incremented by one, because
of the checklist page.
Slimmed down document counting method

By using 'present?' method I've shed a lot unneeded code.
Merge pull request #274 from ministryofjustice/checklist

Checklist