Add new build tool.

bibliogra.py requires Python 2, which is a pain to deal with.  This
commit adds a Go tool that compiles CensorBib from BibTeX to HTML.  The
tool does the bare minimum and is quite strict in the BibTeX format it
expects.

src/footer.go

@@ -0,0 +1,11 @@
+package main
+
+func footer() string {
+	return `<div id="footer">
+Icons taken without modification from
+<a href="https://fontawesome.com/license">Font Awesome</a>.
+</div>
+
+</body>
+</html>`
+}