Expose link command functions.

lib/commands/link.js

@@ -100,7 +100,10 @@ function createLink(src, dst) {
 
 // -------------------
 
-var link = {};
+var link = {
+    linkTo: linkTo,
+    linkSelf: linkSelf
+};
 
 link.line = function (argv) {
     var options = link.options(argv);