feat main: Add proper CLI support

Adds a basic CLI structure with a single "run" command that takes a --file (-f)
and --limit (-l) flag.

--limit can be used to only output certain resource sets.

Closes #4

context/context.go

@@ -2,9 +2,10 @@ package context
 
 import (
 	"encoding/json"
-	"github.com/polydawn/meep"
 	"io/ioutil"
 	"path"
+
+	"github.com/polydawn/meep"
 )
 
 type ResourceSet struct {