update to node v06 compatible deps

lib/mbtiles.js

@@ -2,7 +2,7 @@ var _ = require('underscore'),
     fs = require('fs'),
     Step = require('step'),
     crypto = require('crypto'),
-    zlib = require('zlib'),
+    _zlib = require('_zlib'),
     path = require('path'),
     url = require('url'),
     qs = require('querystring'),
@@ -216,7 +216,7 @@ MBTiles.prototype.getGrid = function(z, x, y, callback) {
             if (err) return callback(err);
 
             try {
-                var grid = zlib.inflate(
+                var grid = _zlib.inflate(
                            !Buffer.isBuffer(row.grid)
                            ? new Buffer(row.grid, 'binary')
                            : row.grid
@@ -227,7 +227,7 @@ MBTiles.prototype.getGrid = function(z, x, y, callback) {
                     }, {});
                 var result = _(JSON.parse(grid)).extend({ data: data });
             } catch (err) {
-                return callback(new Error('Grid is invalid'));
+                return callback(new Error('Grid is invalid:' + err.message));
             }
 
             callback(null, result);
@@ -565,7 +565,7 @@ MBTiles.prototype.putGrid = function(z, x, y, data, callback) {
     var id = crypto.createHash('md5').update(json).digest('hex');
     if (!this._gridCache[id]) {
         // This corresponds to the grid_utfgrid table.
-        this._gridCache[id] = zlib.deflate(new Buffer(json, 'utf8'));
+        this._gridCache[id] = _zlib.deflate(new Buffer(json, 'utf8'));
 
         // This corresponds to the grid_key table.
         this._keyCache[id] = Object.keys(data.data || {});

package.json

@@ -30,11 +30,14 @@
     ],
     "dependencies": {
         "optimist": "0.2.x",
-        "sqlite3": "~2.0.17",
+        "sqlite3": "~2.1.1",
         "step": "0.0.x",
         "sphericalmercator": "1.0.x",
         "underscore": "1.1.x",
-        "zlib": "1.0.x"
+        "zlib": "https://github.com/springmeyer/node-zlib/tarball/master"
+    },
+    "devDependencies": {
+        "expresso": "~0.9.0"
     },
     "engines": {
         "node": ">= 0.4.0"