Merge pull request #8 from DanielStolt/master

Improved, refactored and cleaned up LogentriesAppender.cs.
Updated to version 2.3.6
Added hook to check if the LE queue is empty.

We were having an issue where our app shutdown wasn't recorded because of the background thread nature of the LogEntries writer.

I also added support in case there were multiple LogentriesAppender created
Merge pull request #9 from billrob/master

Added hook to check if the LE queue is empty.
Changed queue to Queue and updated to v.2.3.7
Updated readme to include how to use the blocker.
Merge pull request #10 from billrob/master

Updated readme docs to see how to use it.
Added header for closing background thread section
Merge pull request #1 from logentries/master

Merged changes from logentries/master.