No relative require in locales

This PR rewrote all `require('../moment')` into `require('moment')`

The reason is to decouple the locales from the moment.js file. 
This could cause problems in browser environment, because locale files are not bundled with moment.js, so there should be no relative relation.

In Node.js envirnoment this works fine, because node will lookup moment in the node_modules directory.