+ make Buffer#write support multiple arguments
+ refactor commands using send(command_id){ |buf| buf.write(:custom, data, :for, command) }
- integrate collections method_missing api from jruby wrapper
 
- improved version of save
  - doInsert if not .keys.include?(:_id)
    - generate object id
      - use same algorithm as ObjectID.java
      - or perhaps, use modified uuid gem
  - doUpdate if :_id already exists
 
- add indexing api (ensureIndex) [ look at dbcollection.js ]
 
- support cursors
  - doGetMore to get more data from a cursor
  - doKillCursors to clean up