Merge website content into docs

doc/_static/breathe.css

@@ -14,3 +14,15 @@
 .container .breathe-sectiondef {
   width: inherit;
 }
+
+.github-btn {
+  border: 0;
+  overflow: hidden;
+}
+
+.jumbotron {
+  background-size: 100% 4px;
+  background-repeat: repeat-y;
+  color: white;
+  text-align: center;
+}