Build all "advanced" headers into the "Resources/PrivateHeaders" part of the ENSDK framework.
While the primary public headers can be imported with <ENSDK/ENSDK.h>, the advanced ones don't seem to work with
bracket notation. You can #import "ENSDKAdvanced.h".

The alternate way of doing this is dumping ALL visible headers into the main public headers area, which might end up
being the right thing to do, but right now it's nice not to pollute that area.