Transient annotation for lazy logging

[eshu]

Please, add @transient annotation here:

https://github.com/typesafehub/scala-logging/blob/c8066a7aee6e11265c8d49d6fce9960c92d189ea/src/main/scala/com/typesafe/scalalogging/Logging.scala#L27

The reason was explained here: https://www.mail-archive.com/user@spark.apache.org/msg29010.html

[dbast]

This is not required according to #84

[Atry]

Not required but it is still good to have.

Fixed in #114