Buffered appender to bulk endpoint

Here's a first version of a buffered loggly appender.
I didn't rip the whole thing apart so there are actually some pieces of the original implementation left.
The buffered appender buffers and also has a timer that flushes the buffer after a while if log frequency is too low.

I had a TinyIoCContainer in there but it felt like overkill, what do you think?

@joem-iq @stefanmoser 
Yeah, I realized that after GitHub finally refreshed and I read his comments. I just find log4net's lack of handling this suspicious.