Fixes Issue #25: Incomplete struct definitions cause missing fields. Edit

Here's my in-progress patch to resolve issue #25 by deferring struct entry loading.
This works fine in a simple test case, but still seeing a failure with my more complicated libuv test case.

It seems we don't always get a "complete" definition of the structure from clang.
Not sure yet why this is, but I'll continue looking into it. I'll add a test once I have
a case that reproduces the complex failure I am still seeing.