Fixed PHP-1052: Replace JSON encoding of stream notifications with standard PHP serialize encoding.
Git rid of it in the config files too.
Merged pull request #699
Fixed PHP-1102: php driver throws exception when connect string contains an unresolvable
hostname

If we have any usable connection we should make sure we don't throw an exception and bork.
Unfortunately this means that letting the user know that his connection string is very bad
is difficult and only discoverable through MongoLog - unless the entire seed list is
broken
Add test for only invalid-hostname in seedlist