RUBY-787 Refactor update class to be single update
RUBY-787 BulkUpdate class and specs
Merge pull request #490 from estolfo/bulk-update

Refactor update operation to single and bulk
Typo in spec
Batchable module for spitting Bulk operations
RUBY-787 Adding batchable functionality to BulkDelete
RUBY-787 Adding batchable functionality to BulkUpdate
RUBY-787 Adding batchable functionality to BulkInsert
Use constants for keys
RUBY-787 merge method added to batchable
RUBY-787 Specs for merge on BulkDelete
RUBY-787 Specs for merge on BulkUpdate
RUBY-787 Specs for merge on BulkInsert
RUBY-787 Number of items to batch can equal number of batches
Merge pull request #491 from estolfo/batchable

Batchable module for bulk operations
Call compact on list of messages to dispatch
Return nil if the operation was unacknowledged
Attribute writer for write_concern on bulk operations
Return a new op object when setting write concern
Clearer specs