fix: Remove the base element from layouts

Remove the `base` element from `partials/head.html` to fix the relative
images issue.

Resolves: #6
See also: siegerts/hugo-theme-basic#2

layouts/partials/head.html

@@ -2,7 +2,6 @@
     <meta charset="utf-8">
     <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
     <title>{{ with .Page.Title }}{{ . }} - {{ end }}{{ .Site.Title }}</title>
-    <base href="{{ .Site.BaseURL }}">
     {{ $normalize := resources.Get "css/normalize.css" }}
     {{ $solarized := resources.Get "css/solarized-light.css" }}
     {{ $style := resources.Get "css/style.css" }}