Merge pull request #10 from ilyar/fix/master/issue8

#8 Fix error run npm on win32 platform

Author: arikon

lib/install.js

@@ -82,7 +82,7 @@ function bowerList(options, config) {
 function npmInstallAll(list, options, config) {
     var logger = config.logger || new Logger(),
 
-        npmBin = process.env.NPM || 'npm',
+        npmBin = process.env.NPM || (process.platform === 'win32' ? 'npm.cmd' : 'npm'),
         npmArgs = ['install', options['npm-development'] ? '--development' : '--production'],
         promise = Q.resolve();