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 
Semi off topic, but would we be able to "toString" or force the property to be set as a string? This code was actually added by Devon S.  (https://github.com/jonfreeland/Log4Netly/pull/3) The only issue is that when Loggly parses numerics, it will not add them to the list of pre-defined filterable fields.

Here is an example
![image](https://cloud.githubusercontent.com/assets/3682501/4137596/9752ee26-3388-11e4-8836-3834ccc91236.png)


And the raw JSON

![image](https://cloud.githubusercontent.com/assets/3682501/4137536/0b98cf18-3388-11e4-9c7c-3c9588afa544.png)

And also Loggly support confirms it as well

"Steven replied:
Hi Paul,
I do see those fields as being parsed. I am thinking that the reason you are not seeing them as parsed is because they are not appearing on the Left Hand Navigation. As of now, only string fields will be available .
Regards, 
Loggly Support
"

It's also noted in the documentation that once that data element is viewed as a numeric type, it will never parse the data as a string and it will cause errors in the future ... until the data falls off due to retention.