Export mongoc_log_level_str so projects don't have to copy&paste it
Add missing break

This causing all log types being printed out to stdout
tests: handle max documents in command splitting.
write-commands: don't shadow iter variable.
write-commands: add some debug helpers.
Merge pull request #25 from bjori/log-fixes

mongo_log fixes
log: follow up commit for adding symbols and cleanup.
write-command: respect max batch size even if documents is small.
cluster: use signed size for bson/msg size.
write-command: be a bit more paranoid when generating inserts.
use more natural alignments for key generation
build: bump libbson to master.
build: bump libbson
collection: add mongoc_collection_find_and_modify() helper.

This should simplify the use case for people needing to do find_and_modify.
My hope is that we can maintain this ABI, as it is a lot simpler than
building complex bson documents with all the options.

In the future we may introduce a more "builder" style concept for executing
find and updates, but this should work for now.

Holler if you have any complaints.
examples: use mongoc_collection_find_and_modify().
collection: move doc to be near function.
collection: use createIndexes when posssible for index creation.

2.6 has a new command called createIndexes which should be preferred to
performing an insert on the system.indexes collection.

Upon command not found failure, we insert into system.indexes in the
old style. Contrast this to the situation where we know the server
version/commands and make a decision based on that.
collection: deprecate mongoc_collection_ensure_index()

The ensure_index() indicated, like other legacy drivers, that we were
caching the results of the index creation. We do not, and will not be
doing this in the future. (There are lots of good reasons why calling
ensure index all over the place is a bad idea).

Longer term, we may add a create_indexes() method so you can create more
than one at a time, but for now this will do.
collection: improve name validation.
doc: start on TUTORIAL.md.