add browserify (not yet working) and refactor tree nodes to not be dependent on their parent (currently breaks browser build)

lib/less/environments/node.js

@@ -8,6 +8,9 @@ module.exports = {
     warn: function(env, msg) {
         console.warn(msg);
     },
+    encodeBase64: function encodeBase64(env, str) {
+        return new Buffer(str).toString('base64');
+    },
     getPath: function (env, filename) {
         var j = filename.lastIndexOf('/');
         if (j < 0) {