update to terser v5
replace gulp-remove-code with a rough equivalent in the gulpscript itself
replace gulp-inline with gulp-inline-source-html
remove base64 modules as redundant when running inline-source (does both)
remove crass as redundant when running inline-source (uses csso)
fixup jquery source map comment (but still keep the actual file)

at least now this seems stable enough to start more of the ui tweaking

note that this does not show the correct error line b/c we filter this
through the remover() first

support es6 syntax
use js comment style in custom.js
only minify the custom.js

using 4.x branch, since 5.x wants async / await and more changes to the gulp script

Port of https://github.com/Vasil-Pahomov/ArWs2812 from Arduino to ESP8266
Implementing garland of WS2812

Co-authored-by: Dmitry Blinov <dblinov@blackberry.com>

* Completed kingart curtain switch support:
Added Web UI controls and view in status
Added power up behaviour (nothing, close, open, last position)
Added curtain style (Roller, etc...) for UI status and to be used in MQTT

* Checked commit before PR. Added html gulp static files generated.

* Corrected a code refactor error which make the MQTT messages not handling position from received messages. Added comment to debug tab to show how to enable debug

* Use the maximum compression for gzip. A byte is a byte :)

* Update code/espurna/curtain_kingart.cpp

Co-authored-by: Max Prokhorov <prokhorov.max@outlook.com>

* Variable name prefix update
Added public set position function and curtain count

* Added Scheduler new type : curtain

* Add curtain schedule support and correct the 12h bug when adding a slot (00:00 after refresh). Default Hour is 12h

* Code cleaning.
Schedule support.
Light support is having an issue with new schedules corrected here.

* I let do better by the specialists

* Curtain init statues

* Coding style corrections

* Removed debug stuff from now - will be back later with the right way

* rebuild webui

* revert 435f1c5e03 schHour default, rebuild ui

Co-authored-by: Eric Chauvet <eric.chauvet@test-tree.com>
Co-authored-by: Max Prokhorov <prokhorov.max@outlook.com>

- use setOriginalsFromValues function right after elements had changed and
**only** with those elements
- add checkbox handling to setOriginalsFromValues to match hasChanged
- apply hasChanged after value is set to refresh originals after saving
- change parts that already set 'original' attribute manually

This was sort-of broken, because original attr never worked as intended. 
Also fix possible OOM for large WebUI images, since sending full config each time means that we need more memory to buffer and parse it.

1. Add thermostat to the espurna_modules in progmem.h
2. Add thermostat to webui, gulp, html, js.
3. in general.h MQTT_USE_JSON returned to 0 by default and 1 if thermostat enabled.

Bump npm version installed by travis
Update package-lock for latest npm version
Bump packages versions and clean-up unused
Missing datatables.js images to avoid warnings

tabs to spaces for consistency