Merge branch 'new-markdown' into 'master'

markdown fixes

old
![Screenshot_2016-01-05_10.49.46](/uploads/731f0e83ceefa74650ea27f8dca67b35/Screenshot_2016-01-05_10.49.46.png)

new
![Screenshot_2016-01-05_10.51.51](/uploads/85a82b2a589f9a4ad3dd47c6de3b89d7/Screenshot_2016-01-05_10.51.51.png)


See merge request !2295

app/assets/stylesheets/framework/typography.scss

@@ -54,17 +54,17 @@
 
   h3 {
     margin: 24px 0 12px 0;
-    font-size: 1.25em;
+    font-size: 1.1em;
   }
 
   h4 {
     margin: 24px 0 12px 0;
-    font-size: 1.1em;
+    font-size: 0.98em;
   }
 
   h5 {
     margin: 24px 0 12px 0;
-    font-size: 1em;
+    font-size: 0.95em;
   }
 
   h6 {