Rename 'ConferenceController' to 'ConferencesController', and 'ProposalController' to 'ProposalsController'

app/views/proposal/_encouragement_text.html.haml

@@ -1,24 +0,0 @@
-%p.lead
-  - if @program.event_types.any?
-    You can submit proposals for
-    = "#{event_types(@conference)}."
-  - if @program.tracks.any?
-    Proposals should fit in one of the
-    = "#{pluralize(@program.tracks.count, 'track')}:"
-    = "#{tracks(@conference)}."
-  - if @program.cfp_open?
-    The submission period has begun
-    %em.notranslate
-      = @program.cfp.start_date.strftime('%A, %B %-d. %Y')
-    and closes
-    %em.notranslate
-      = @program.cfp.end_date.strftime('%A, %B %-d. %Y.')
-    That means you have
-    %b.notranslate= pluralize(@program.cfp.remaining_days, 'day')
-    left!
-    Remember
-    %span.notranslate
-      = @conference.title
-    will only be as good as the content you present. Submit early, submit often!
-  -else
-    The submission period is closed now.