Support Jackson for JSON

[cemo]

Hi, thanks for sharing. Is it possible to use Jackson instead of AliBaba JSON Library. Supporting both of them might be a good idea as well. One can check that which Library is available in classpath and can use it as a JSON converter. What do you think?

[hengyunabc]

FastJSON is one of the fastest json libraires.

Zabbix-sender is a smiple project, I want keep it simple.

So I will not support both Jackson and FastJSON.