Format money as according to the style guide

Money without pence should be displayed as integers
Add drop-off legalisation transaction
Tidy up TransactionCalculator
Merge remote branch 'origin/legalisation'
Use the updated slugs for epdq transactions
Add the legalisation transactions to the index page
Merge pull request #3 from alphagov/slug-changes

Update the transactions to use the new slugs and titles
Merge in master and fix conflicts
Remove .DS_Store from local gitignore
Add new transactions and update slugs for others