Update dependency to a more recent version of cffi; cffi is moving pretty quickly, it doesn't make much sense to shoot for any backwards compatibility at this point.
Remove the FILE declaration.  cffi does this now, and declaring it again breaks things.
Attempt not to use some of cffi's internals (armin said so)
Get tests.c passing again

The API for extracting a byte string out of a cffi buffer changed.  Update code to reflect that.
Fix a great many more failing tests by making the same bytes(api.buffer(x)) -> api.buffer(x)[:] change in more places
Use the new api.openssl object to introspect the existing BIO types.
Merge pull request #13 from exarkun/cffi-cleanups

Cffi cleanups

Unit tests all pass ok for me. My apologies for taking soooo long to getting to this pull request.