Fixed picker.js throwing random requirejs script error on development

In Community (development), this error is rather constant than random:

![screenshot 2014-12-30 15 01 18](https://cloud.githubusercontent.com/assets/1451471/5579064/c09d2b3a-9034-11e4-8ddc-66264468ece5.png)

Putting `datepicker` components inside `requirejs` config seems to fix this issue. Console is clean :clap: 

Btw, made an update  `v3.3.1 -> v3.5.4` (last version before `v4.0.0`).