feat: faster parser (#3)

* fix(load): support nested objects

* feat: initial golang parser

Moves most of load.libsonnet to a Golang app for hopefully much faster
parsing (fingers crossed)

* feat(fast): nested objects, subpackages

* feat: incorporate fast mode into main binary

Moves the work done in the fast directory into the main executable,
removing the Jsonnet based parser in favor of the much faster Golang one.

pkg/render/render.go

@@ -15,6 +15,7 @@ func Render(pkg docsonnet.Package) map[string]string {
 }
 
 func render(pkg docsonnet.Package, parents []string, root bool) map[string]string {
+	fmt.Println("render", pkg.Name)
 	link := "/" + strings.Join(append(parents, pkg.Name), "/")
 	if root {
 		link = "/"