add new tag specs for show-all-tags partials where tags are clickable

Now the show-event page for single event should eventually have a list
of all available tags for adding to the visible event.
tidy up routes file
pass tags controller spec to show all available tags
amend clickable tags feature test to find non link tag texts
auto add whitespace to tag controller
update Event tag specs and mark buggy ajax feature test pending
pass updated EventTag model test
update routes for tidiness, add new event_tag post route
create event tags controller
extract views to partials and create this_event_tags partial
style selected tags
add magic ajax request to tie it all together