- added (read-preference ..) to create ReadPreference instances
- added the facility to supply read preferences to (fetch …)
- added function to get/set a WriteConcern on a per-collection basis
- added function to get/set a ReadPreference on a per-collection basis
- added function to set a ReadPreference on a per-connection basis
Merge pull request #122 from niclasmeier/master

Support for ReadPreferences