Add debug logs for SMTP notifications
Fix hanging java.net.SocketInputStream.socketRead0

Add System Properties proper to Oracle HotSpot JVM to enable
default SO_TIMEOUT and also default connection timeout:
-Dsun.net.client.defaultReadTimeout=30000
-Dsun.net.client.defaultConnectTimeout=60000

Those should prevent hanging client Threads because of unresponsive
ESTABLISHED connection.

References:
http://perfstories.wordpress.com/2012/08/14/be-aware-of-sun-oracle-networking-properties/
http://docs.oracle.com/javase/7/docs/technotes/guides/net/properties.html