use rimraf for windows support

lib/fsutil.js

@@ -5,6 +5,7 @@ var path = require('path');
 var constants = require('constants');
 var _ = require('underscore');
 var mkdirp = require('mkdirp');
+var rm = require('rimraf');
 // node v6 -> v8 compatibility
 var existsSync = require('fs').existsSync || require('path').existsSync;
 
@@ -50,32 +51,6 @@ function readdir(filepath, callback) {
     });
 };
 
-
-// Recursive rm.
-function rm(filepath, callback) {
-    var killswitch = false;
-    fs.lstat(filepath, function(err, stat) {
-        if (err) return callback(err);
-        if (stat.isFile() || stat.isSymbolicLink()) return fs.unlink(filepath, callback);
-        if (!stat.isDirectory()) return callback(new Error('Unrecognized file.'));
-        Step(function() {
-            fs.readdir(filepath, this);
-        },
-        function(err, files) {
-            if (err) throw err;
-            if (files.length === 0) return this(null, []);
-            var group = this.group();
-            _(files).each(function(file) {
-                rm(path.join(filepath, file), group());
-            });
-        },
-        function(err) {
-            if (err) return callback(err);
-            fs.rmdir(filepath, callback);
-        });
-    });
-};
-
 // Utility function. Implements a `cp -r` like method in node.
 function cprSync(from, to) {
     var stat = fs.lstatSync(from);

package.json

@@ -37,6 +37,7 @@
         "JSV": "4.0.x",
         "sax": "0.6.x",
         "request": "2.x",
+        "rimraf": "^2.5.2",
         "step": "~0.0.5",
         "mbtiles": "~0.8.2",
         "mapnik": "3.5.13",