Cannot export as AMF

Bug Report
============
**Steps to Reproduce**
1. export phil a mint out as an amf file type
2. 
3. 

**Expected Behavior**

**Actual Behavior**

**MatterControl Build Number**
(To find this, go to the MatterControl menu in the top left and click "About MatterControl")

**Operating System Version**

**Printer Make/Model**
