Revert "add is_keynote attribute to event_types"

This reverts commit 96253b1fe048e2052fc35e961c5afbf27d0ef740.

Conflicts:
	app/models/conference.rb

app/views/conference/_program.html.haml

@@ -24,19 +24,19 @@
           = link_to(conference_schedule_path(@conference.short_title), class: 'btn btn-default btn-lg') do
             Full Schedule
 
+
   %h3.text-center
     Don't miss out!
   %br
   - if @conference.events.highlights.any?
     .row
       .col-md-12
-        - @conference.events.highlights.each_slice(3) do |slice|
+        - @conference.events.highlights.each_slice(2) do |slice|
           .row.row-centered
             - slice.each do |event|
-              .col-md-4.col-centered.col-top.highlights
+              .col-md-6.col-centered.col-top.highlights
                 %p.text-center
                   %b= event.title
-                  by #{event.speakers.first.name}
                 %h5.text-center
                   = simple_format truncate(event.abstract, length: 500, separator: ' ')
                   = link_to "Read More", conference_proposal_path(@conference.short_title, event)