* Use generic typechecks, OTA add followRedirects

* revamp using is_detected

* relative include

* mention ts draft instead, fix c++17 includes (still not buildable)

* typo

* Always create WiFiClient pointer

* Remove old CREATE_CHECK macro

* do not create wificlient obj when running old Core

* Fix SSL check callback function definition

* Print secure client check as string

* Rework MQTT sync client configuration

* MQTT_LIBRARY_...

* comments

* fix not doing any checks for bearssl, remove afterconnected template for mqttclient

* comments

* comments

* secure bool stub

* typos, always include sc helpers

* fix on_fingerprint return type

* typo

* typo

* indent

* tag is already in config obj

* generate mqtt featureset string at compile time

* reword again

* trusted_root_ca

* Core 2.6.0+ fixes

* fix env -> config, run travis04 job

* don't duplicate free heap in frag data, use single stats struct

* fix dtostrf warnings, bump buffer sizes

* ...and even less words for fragmentation stat

- update every dynamicjsonbuffer with fixed size constructor argument
- change to ws callback registration to use a class builder (just cosmetic)
- test multiple ws data callbacks for each module
- remove some of the static strings in favour of ws data callback
- improve sensor ws callback data size, remove duplicated strings
- use static buffer in wsDebugSend
- postpone wsSend until loop, implement wsPost to allow other modules to queue message callbacks. remove Ticker based ws callbacks for data
- update WebUI files

- add httpupdate ota impelementation
- move async ota into a separate module
- support bearssl & axtls through wificlientsecure
- allow to disable arduino ide ota module

* Update encoder

- import modified Encoder library
- customize minimum delta value

* minimum delta in header config

* fixup! minimum delta in header config

* fix dead code, actually use interrupts

* move static class methods to normal funcs, apply namespace

* drop hardcoded register use

- use peripheral api (see cores/esp8266/esp8266_peri.h)
- remove bitmask and register struct members

* add a note about changes

* fixup! add a note about changes

- chain debugSend_P into basic _debugSend instead of duplicating code, pass va_list between them
- check if new[] call was successful
- when possible, use stack buffer and fallback to heap buffer only when it is more that 64 chars

* debug: heap fragmentation stat

* Rework method detection

- return check integral type as a result of detection instead of method type
- type-tagging instead of enable_if

* fix alias

* typo

* only need one bool_type instance

* Move heap debug into HeapStats header

- don't show fragmentation stats on the first call
- prettify fragmentation display
- pack function params into helper struct
- naming

* pass external flag instead

* add missing prototypes

- wrapper NTPClient class to avoid inadvertently calling NTP::getTime() while
setting things up
- only call NTP::getTime() when in loop(), install async TimeLib
sync provider and manually set TimeLib time
- randomize sync and delay times

This reverts commit 1471a632bb.