Merge pull request #1 from soniam/master

Adding distinction between iterable and items
Merge pull request #2 from soniam/master

Fixed to match mongo 2.3
Merge pull request #3 from soniam/master

unique index support
Merge pull request #4 from soniam/master

adding regex support for collection items
Fix for when ensure_index is presented with a list of keys.
Adding support for compound unique indexes
Fixing issues with find() on non existing properties