After libdazeus, now switch dazeus itself to jansson, the JSON library maintained by Petri Lehtinen. Fixes #16.

* UTF8 handling is a bit different now: the bot will never send \uXXXX codes, but will immediately send UTF-8 as is (so "ƒøø", for example, instead of "\u0192\u00f8\u00f8").
* The workaround for broken libjson code has been removed!