Merge pull request #117 from MargaretLangley/master

invoice.back_page used to choose between back page or blank page. No-pri...
rubocop update - fixed style bugs
brakeman updated, selenium update
BUGFIX Invoice.products.total_arrears return 0 if last is nil?
property client autocomplete_source uses client_list helper
BUGFIX payment totals not being added (and tests not picking this up)
Capistrano gems incremented
debit added debut to_s
BUGFIX ProductMakers were missing automatic_payment in arrears creation.
Product were missing validates. product.to_s refactored
property client autocomplete_source uses client_list helper
comment appears on front page