Fixed PHP-683: Add support for the connectTimeoutMS connection parameter
Add support for wTimeoutMS in the connection string as per the spec

We previously supported the incorrectly named "wTimeout" setting, and
continue to do so. See PHP-613
Fixed PHP-684: add support for socketTimeoutMS

Also renamed that ambigous PHP_MONGO_DEFAULT_TIMEOUT to
PHP_MONGO_DEFAULT_WTIMEOUT

We now apply the socketTimeoutMS option if the user hasn't explicitly
modified the MongoCursor::$timeout variable
Fixed PHP-685: wtimeout option is not supported per-query

We simply never checked for the option in the options array.
Now we'll fall back on the MongoCollection->wtimeout (which inherits the
wtimeout from MongoDB->wtimeout, which is set by the connection string,
or defaults to PHP_MONGO_DEFAULT_WTIMEOUT)