bulk divide into actions, closes #265

[lionvs]

This is manual fix for issue #265

If group of bulk operations have more than 1000 operations, it divides the group into smaller groups of 1000 or less.

This work-around needs to be removed when it will be implemented in mongodb driver.

[chriswininger]

Be nice to see this pulled in. I just updated to 2.3.0 and immediately started running into this

[saintedlama]

@sorribas @watson @mafintosh What do you think about it? Could not find the reason for this issue but the fix would work. Merge it as temporary workaround?

[aPoCoMiLogin]

Any reason why this is not merged yet ?

[vctfernandes]

Any reason why this is not merged yet ? [2]

[saintedlama]

Implemented in commit 8c301a3 by adding conditions that open a new bulk cmd if the current documents/updates/deletes length exceeds the max bulk size. This implementation avoids copying possibly large bulks.