Bigarray support.
Tests for bigarray sizes.
Test passability for bigarrays.
Tests for bigarray alignment.
Tests for bigarray type printing.
Test viewing ctypes-managed memory using bigarrays.
Test using ctypes to view bigarray-managed memory.
Tests for passing and returning bigarrays to and from C.
Bigarray lifetime tests.
Merge pull request #36 from yallop/bigarray

Bigarray support
C syntax (WIP).
Stub-generating implementation of the struct-building interface.
Test retrieving struct layout from C.

The plumbing needs some work, but the basic idea is there.