this moves the bson version up to 1.0.7 to agree with the mongo (and bson_ext) gems. it also updates BSON::ObjectID to BSON::ObjectId across the board and fixes a few tests that broke.

I'm not sure why you're currently using mongo 1.0.7 and bson 1.0.4 though.

in particular, this solves the message:

**Notice: C extension not loaded. This is required for optimum MongoDB Ruby driver performance.
You can install the extension as follows:
gem install bson_ext

If you continue to receive this message after installing, make sure that the
bson_ext gem is in your load path and that the bson_ext and mongo gems are of the same version.

when mongo pulls in bson 1.0.7 and mongoid pulls in 1.0.4.