Update Bootstrap to v4.1, fix chosen.js and pagedown on multiple sites

app/views/submissions/index.html.slim

@@ -9,7 +9,7 @@ h1 = Submission.model_name.human(count: 2)
     = f.select(:cause_eq, Submission.select(:cause).distinct.map(&:cause).sort, class: 'form-control', prompt: t('activerecord.attributes.submission.cause'))
 
 .table-responsive
-  table.table
+  table.table.mt-4
     thead
       tr
         th = sort_link(@search, :exercise_id, t('activerecord.attributes.submission.exercise'))

app/views/submissions/show.html.slim

@@ -1,3 +1,10 @@
+- content_for :head do
+  // Force a full page reload, see https://github.com/turbolinks/turbolinks/issues/326.
+     Otherwise, code might not be highlighted correctly (race condition)
+  meta name='turbolinks-visit-control' content='reload'
+  = javascript_include_tag(asset_path('highlight.min.js', type: :javascript))
+  = stylesheet_link_tag(asset_path('highlight-default.css', type: :stylesheet))
+
 h1 = @submission
 
 = row(label: 'submission.exercise', value: link_to(@submission.exercise, @submission.exercise))
@@ -5,9 +12,9 @@ h1 = @submission
 = row(label: 'submission.cause', value: t("submissions.causes.#{@submission.cause}"))
 = row(label: 'submission.score', value: @submission.score)
 
-h2 = t('activerecord.attributes.submission.files')
+h2.mt-4 = t('activerecord.attributes.submission.files')
 
 ul.list-unstyled
   - @files.each do |file|
-    li.panel.panel-default
-      .panel-body = render('shared/file', file: file)
+    li.card.mt-2
+      .card-body = render('shared/file', file: file)

app/views/submissions/statistics.html.slim

@@ -4,7 +4,7 @@ h1 = @submission
 = row(label: 'submission.score', value: @submission.score)
 = row(label: '.siblings', value: @submission.siblings.count)
 
-h2 = t('.history')
+h2.mt-4 = t('.history')
 
 .table-responsive
   table.table