Check that user role doesn't already exist before sharing. Fixes #362

Fixes #307 - Single invitation email issue

Fixes #289 - when sharing plan with invalid email

Bugfixes for invitations/ password change. Fixes #268, #271.

Fixed nil user variable when generating HTML code for sharing notification. DMPRoadmap/roadmap#286 ...

added condition for avoiding sharing plan with email matching plans owner. DMPRoadmap/roadmap#286

Added message to internationalisation files. DMPRoadmap/roadmap#286

Merge branch 'development' into development

Updated ActionMailer deliver calls to deliver_now because deliver is deprecated in Rails 5

updated function call to sharing_notification mailer

fixes issue with changing roles for a shared plan #231

Added obj_name param to the generic error message handler on application_controller. Updated all save error handling to render the page rather than redirect DMPRoadmap/roadmap#227

added error messaging to roles controller

fixed merge conflicts after rebase

added roles controller tests and updated controller to use strong params and handle failures properly

implimented new role backend according to #219

updated roles controller to use strong parameters

Replaced I18n.t(...) from controllers. DMPRoadmap/roadmap#98

saved roles_controller changes

updated roles_controller and model functions

began updating roles