Keep await_data and get_more without a limit set working.
Fixed memory leak and error detection with findOne.
Removed superfluous code.
Fixed checking for dead-ness.
Fixed two test cases.
Make sure to handle cursor errors with getmore.
We need to check the error after having obtained the result.

In some cases (maxtimems) the server puts the error information in a returned
document, which we of course need to parse before checking for.
Fixed a valgrind use-after-free warning.
Fixed the gridfs functionality

MONGO_METHOD--