set up base template

- set up top nav
  - auto generate menu from `main`
  - configurable brand (can be hidden or custom, defaults to site title)
  - top nav can be configured to be sticky
- css in top, js at the end of body
- default google analitycs template added to base
- added highlight.js

layouts/partials/nav.html

@@ -0,0 +1,41 @@
+<nav class="navbar navbar-expand-lg navbar-dark bg-primary{{ if and (isset $.Site.Params "fixednav") $.Site.Params.fixednav }} fixed-top{{ end }}">
+  <div class="container">
+    {{ if or ( not ( isset $.Site.Params "showbrand" ) ) $.Site.Params.showbrand}}
+      <a class="navbar-brand" href="/">
+        {{ default $.Site.Title $.Site.Params.brand}}
+      </a>
+    {{ end }}
+    <button class="navbar-toggler my-1" type="button" data-toggle="collapse" data-target="#navbar" aria-controls="navbar"
+      aria-expanded="false" aria-label="Toggle navigation">
+      <span class="navbar-toggler-icon"></span>
+    </button>
+
+    <div class="collapse navbar-collapse" id="navbar">
+      <ul class="navbar-nav mr-auto">
+        {{ $currentPage := .}}
+        {{ range .Site.Menus.main }}
+          {{ if .HasChildren }}
+            <li class="nav-item dropdown{{ if $currentPage.HasMenuCurrent "main" . }} active{{ end }}">
+              {{ if .URL }}
+                <a href="{{ .URL }}" class="nav-link dropdown-toggle" role="menu" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">{{ .Name }}</a>
+              {{ else }}
+                <a href="#" class="nav-link dropdown-toggle" role="menu" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">{{ .Name }}</a>
+              {{ end }}
+              <div class="dropdown-menu">
+                {{ range .Children}}
+                  <a href="{{ .URL }}" class="dropdown-item{{ if $currentPage.IsMenuCurrent "main" . }} active{{ end }}">{{ .Name }}</a>
+                {{ end }}
+              </div>
+            </li>
+          {{ else }}
+            <li class="nav-item{{ if $currentPage.IsMenuCurrent "main" . }} active{{ end }}">
+              <a class="nav-link" href="{{ .URL }}">{{ .Pre }}{{ .Name }}
+                  {{ if $currentPage.IsMenuCurrent "main" . }}<span class="sr-only">(current)</span>{{ end }}
+              </a>
+            </li>
+          {{ end }}
+        {{ end }}
+      </ul>
+    </div>
+  </div>
+</nav>