PHP-1258: Run the testsuite against alternative storage engines
PHP-1258: Be able to skip skip a test based on storage engine
PHP-1258: Skip tests that expect certain storage engines

See PHP-1225 and PHP-1226
PHP-1276: Duplicate Key error message changed
PHP-1276: Pass proper wireprotocol flags when executing commands on secondaries
PHP-1276: The flag is "max cursors", not "exactly this many cursors"
PHP-1276: s/cmd/command/ in 2.8
PHP-1276: this hardly could ever had worked
Fixed PHP-1278: runcommand memory leak