RUBY-596 Basic map/reduce implementation
RUBY-596 Set or get finalize function
RUBY-596 Set or get jsMode flag
RUBY-596 Set or get output mode/collection
RUBY-596 Set or get scope
RUBY-596 Set view options properly on map/reduce
RUBY-596 Allow map/reduce output to collection
RUBY-596 Move common view cursor behaviour into iterable module
RUBY-596 Validate result of map/reduce operation
RUBY-596 map/reduce spec in readable spec
Merge pull request #489 from mongodb/map-reduce

RUBY-596 Map reduce