#558 - Simplify NUX account creation

Issue: https://github.com/wordpress-mobile/WordPress-iOS/issues/558

Old:
![4bea9f44-4e3f-11e3-8643-8d6a306e995f](https://f.cloud.github.com/assets/3904502/1564491/cac13c60-506f-11e3-90f0-a1b8f6c45eb7.png)

New:
![ios simulator screen shot nov 18 2013 8 36 32 am](https://f.cloud.github.com/assets/3904502/1564492/cd8a4be4-506f-11e3-81ab-4196f683d996.png)