New entries with a Date field show changed status

**- Do you want to request a *feature* or report a *bug*?**
bug

**- What is the current behavior?**
Entries with a Date field will ask the user whether or not they want to save changes, when the entry was just created.

**- If the current behavior is a bug, please provide the steps to reproduce.**
1. Create a new entry (with a Date field).
2. Try to leave it (click the home button).

**- What is the expected behavior?**
If nothing has been added, the entry should not prompt to save.

**- Please mention your CMS, node.js, and operating system version.**

0.5.1 (actually master)