tests; handle mongo 2.3.2+ err messages
MongooseBuffer should cast numbers as well
fixed; docs with Buffer _ids equality
added; promises/A+ comformancy

https://github.com/promises-aplus/promises-spec

adds promise#then, promise#reject
use mpromise
updated; muri 0.2.0
Cast string 'true'/'false' to boolean value
Update test/schema.test.js for cast 'true'/'false'
just support Bool->String->Bool
updated; mocha 1.8.1
adjust test for muri update
allow non-strict sets and updates

useful when cleaning up old properties that are no longer in the schema.

http://bytes.goodeggs.com/post/36553128854/how-to-remove-a-property-from-a-mongoosejs-schema
updated; muri to 0.3.0
added; removing subdoc with _id value support

closes #1278