Set isDir to false for non-existant directory

The PR for issue #45 resolves problems for `readdirRecursive`, but not for `readdirRecursiveSync`. This patch sets `isDir = false` when a directory cannot be found, effectively ceasing further processing.

lib/wrench.js

@@ -28,7 +28,7 @@ exports.readdirSyncRecursive = function(baseDir) {
  curFiles,
  nextDirs,
  isDir = function(fname){
- return fs.statSync( _path.join(baseDir, fname) ).isDirectory();
+ return fs.existsSync(_path.join(baseDir, fname)) ? fs.statSync( _path.join(baseDir, fname) ).isDirectory() : false;
  },
  prependBaseDir = function(fname){
  return _path.join(baseDir, fname);