* allow setting readpreference when using rest api.
* take out partially complete unit test.
* oops. nit
* Include read preference option for find directly from api and adding few more tests
* Adding catch for all tests
* Keep same check for get and find
* Turn read preference case insensitive
* Includes and subqueries read preferences through API
* Fixing bugs regarding changes that were done in master branch during the last year
* Changing behavior to make includeReadPreference and subqueryReadPreference to follow readPreference by default