Fix width of result count

After b207dd9, the result count was mistakingly being applied a max-width
of 66% from the core. This commit correctly nests it inside
.signup-content.
Add initial documentation to finder-frontend

with @evilstreak @bestie @alicebartlett @themitchell @kalleth
Merge pull request #81 from alphagov/add-documentation

Add initial documentation to finder-frontend
Merge pull request #82 from alphagov/fix-width-for-result

Fix width of result count
Parse six digit dates correctly

With the new Date Facet added in 3376192, Ruby's `Date.parse` method was
parsing six digit dates the wrong way round, so 25/09/14 would be parsed
as 14th September 2025. This commit fixes that by checking if it's a 6
digit date and then building the correct Date, if it doesn't match it
hands the input to `Date.parse`.