Another round of splash design

* Add map to splash
* Reverse venue<->conference relation
* Split venue address into fields
* Don't go through venue for lodgings anymore

app/views/conference/_sponsors.html.haml

@@ -12,16 +12,21 @@
         wouldn't be possible! 
   - @conference.sponsorship_levels.each do |sponsorship_level|
     -if sponsorship_level.sponsors.any?
-      .row
-        .col-md-12.text-center
-          %h3
-            = sponsorship_level.title
       - sponsorship_level.sponsors.each_slice(3) do |slice|
-        .row
+        .row.row-centered
           - slice.each do |sponsor|
-            .col-md-4
-              = link_to("http://#{sponsor.website_url}", class: 'thumbnail') do
-                = image_tag(sponsor.logo(:large), alt: "#{sponsor.name} Logo", title: "#{sponsor.description}")
+            .col-md-4.col-centered.col-top
+              .thumbnail
+                - if sponsor.logo.blank?
+                  %h3.text-center
+                    = link_to(sponsor.website_url, title: "#{sponsor.name}") do
+                      = sponsor.name
+                - else
+                  = link_to(sponsor.website_url, class: 'thumbnail') do
+                    = image_tag sponsor.logo, class: "img-responsive img-sponsor img-sponsor-#{sponsorship_level.position}", title: "#{sponsor.name}"
+                .caption
+                  -if sponsor.description.present?
+                    = markdown(sponsor.description)
   -if @conference.contact and !@conference.contact.sponsor_email.blank?
     .row
       .col-md-12