Fix help page UI

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

app/assets/stylesheets/sections/help.scss

 .documentation {
-  padding-bottom: 10px;
-  p {
-    padding: 10px 14px;
+  h1 {
     margin: 0;
   }
 
+  h2 {
+    font-size: 20px;
+  }
+
   li {
     line-height: 24px;
     color: #888;

app/views/help/index.html.haml

@@ -36,7 +36,7 @@
   .col-md-8
     .panel.panel-default.documentation
       .panel-heading Documentation
-
+      .panel-body
         = preserve do
           - readme_text = File.read(Rails.root.join("doc", "README.md"))
           - text = readme_text.dup