Gst enh livestatus query

as a follow up pull request #186 I am removing the code that stops callers from inserting empty lines into queries (since it did not logically belong to that pull request).

In this pull request I also change Livestatus.query() so it calls self.write() internally instead of self.raw_query() which is what made the original patch necessary to begin with because it broke the unit tests.

Please take a look and give feedback.