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

@@ -36,9 +36,9 @@
   .col-md-8
     .panel.panel-default.documentation
       .panel-heading Documentation
-
-      = preserve do
-        - readme_text = File.read(Rails.root.join("doc", "README.md"))
-        - text = readme_text.dup
-        - readme_text.scan(/\]\(([^(]+)\)/) { |match| text.gsub!(match.first, "help/#{match.first}") }
-        = markdown text
+      .panel-body
+        = preserve do
+          - readme_text = File.read(Rails.root.join("doc", "README.md"))
+          - text = readme_text.dup
+          - readme_text.scan(/\]\(([^(]+)\)/) { |match| text.gsub!(match.first, "help/#{match.first}") }
+          = markdown text