Add serialization and logging support.

[giltene]

One if the very useful features other language implementations share (including Java, C, C#, python, JS, and to some degree Rust) is support for a common serialization format and a common log file format. The formats are captured in code, but also in https://github.com/HdrHistogram/HdrHistogram.NET/wiki . Logging in these formats will allow you to use tools like https://github.com/HdrHistogram/HistogramLogAnalyzer and https://hdrhistogram.github.io/HdrHistogramJSDemo/logparser.html to visulize histogram logs, and/or to transport histogram data across the wire.