ArduinoJson 5.6.7

* Fixed `array[idx].as<JsonVariant>()` and `object[key].as<JsonVariant>()`
* Fixed return value of `JsonObject::set()` (issue bblanchon#350)
* Fixed undefined behavior in `Prettyfier` and `Print` (issue bblanchon#354)
* Fixed parser that incorrectly rejected floats containing a `+` (issue bblanchon#349)

ArduinoJson 5.6.6

* Fixed `-Wparentheses` warning introduced in v5.6.5 (PR bblanchon#335 by @nuket)
* Added `.mbedignore` for ARM mbdeb (PR bblanchon#334 by @nuket)
* Fixed  `JsonVariant::success()` which didn't propagate `JsonArray::success()` nor `JsonObject::success()` (issue bblanchon#342).

ArduinoJson 5.6.5

* `as<char*>()` now returns `true` when input is `null` (issue bblanchon#330)

ArduinoJson 5.6.4

* Fixed error in float serialization (issue bblanchon#324)

ArduinoJson 5.6.3

* Improved speed of float serialization (about twice faster)
* Added `as<JsonArray>()` as a synonym for `as<JsonArray&>()`... (issue bblanchon#291)
* Fixed `call of overloaded isinf(double&) is ambiguous` (issue bblanchon#284)

ArduinoJson 5.6.2

* Fixed build when another lib does `#undef isnan` (issue bblanchon#284)

ArduinoJson 5.6.1

* Added missing `#pragma once` (issue bblanchon#310)

ArduinoJson 5.6.0

* ArduinoJson is now a header-only library (issue bblanchon#199)

ArduinoJson 5.5.1

* Fixed compilation error with Intel Galileo (issue bblanchon#299)

ArduinoJson 5.5.0

* Added `JsonVariant::success()` (issue bblanchon#279)
* Renamed `JsonVariant::invalid<T>()` to `JsonVariant::defaultValue<T>()`