Replace obvious tooltips. Fix line-height for top nav

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/assets/stylesheets/generic/common.scss

@@ -385,7 +385,7 @@ table {
     a {
       padding: 15px;
       font-size: 20px;
-      line-height: 27px;
+      line-height: 28px;
       color: #7f8fa4;
       border-bottom: 2px solid transparent;
 

app/helpers/events_helper.rb

@@ -30,7 +30,6 @@ module EventsHelper
       class: "event-filter-link btn btn-default #{active}",
       id:    "#{key}_event_filter",
       title: "Filter by #{tooltip.downcase}",
-      data:  { toggle: 'tooltip', placement: 'top' }
     }
 
     link_to request.path, link_opts do