Fix Folder Detection API

[ohsh6o]

Old Google Apps Script tutorials are incorrect or outdated, and iterator functions for folder data do not work, these need to be fixed.

7:50:37 PM	Error	
TypeError: folder.next is not a function
Mapper.pickExistingFile	@ Code.gs:115
Mapper.openTraceFile	@ Code.gs:128
Mapper.handler	@ Code.gs:160
run	@ Code.gs:4