Clean up references to the Flume 0.9 TailSource and recommendations to use Exec source to tail files
Clean up references to the Flume 0.9 TailSource and recommendations to use Exec source to tail files

Flume has Spooling Directory Source and Taildir Source now, so there's no need to use workarounds such as the Exec source to tail files.

This closes #88

Reviewers: Denes Arvay, Jeff Holoman

(Peter Ableda via Bessenyei Balázs Donát)

tinawenqiao/flume,szaboferee/flume,iaiengxia/flume,iaiengxia/flume,tinawenqiao/flume,iaiengxia/flume,tinawenqiao/flume,iaiengxia/flume,szaboferee/flume,tmgstevens/flume,tmgstevens/flume,tinawenqiao/flume,szaboferee/flume,szaboferee/flume,tmgstevens/flume,tmgstevens/flume