Add a testcase for PHP-698 (segfault on MongoClient->close() with open cursor)
Add sharding and replicaset variations of PHP-698, just in case :)
Merged Pull Request #411

* pull-request/411:
  Add sharding and replicaset variations of PHP-698, just in case :)
  Add a testcase for PHP-698 (segfault on MongoClient->close() with open cursor)
PHP-771: Fix fragile timing expectation in is_master_interval test

While fixing the test, also update it to the newer format.
Merged pull request #412