* fixed endless loop while switching CMT frequency
* removed obsolete "retries" field from settings #1224
* fixed crash while defining new invertes #1224
* fixed default frequency settings
* added default input power to `400` while adding new inverters
* fixed color of wifi RSSI icon #1224
* fix Contrast for Nokia Display #1041
* attempt to fix#1016 by improving inverter status
* added option to adjust effiency for yield (day/total) #1028
improved wifi initial connection - especially if station wifi is not available #509
removed new operators from web.h (reduce dynamic allocation)
improved sun calculation #515, #505
fixed wifi auto reconnect #509
added disable night communication flag to MQTT #505
changed MQTT publish of `available` and `available_text` to sunset #468
added icons to index.html, added wifi-strength symbol on each page
moved packet stats and sun to system.html
refactored communication offset (adjustable in minutes now)
removed wrong "inverter type can't be detected!" messages
repaired NTP and static IP #459
MQTT status about availability and produce are retain messages now
* fix negative temperature (OpenDTU issue 246)
* added plausibility check based on payload length
* prepared project for splitting into library and end-user-esp
* added donation link to index.html
* deactivated disclaimer temporarily
* improved web serial console
* added multi inverter total values (published through MQTT)
* fixed: after boot there were transferred wrong data because of incorrect assignment (mqtt, visualization)
-> not tested with sun
+ command queue
+ feedback from inverter for actual power limit via InfoCmd -> SystemConfigPara (0x05)
+ REST API will enqueue a new info command
+ change in power limit will enqueue infocm to get actual power limit
+ actual power limit is available under mqtt topic <TOPIC>/<NAME>/ch0/PowerLimit ALWAYS in percent
+ Firmware information will be requested automatically up on start of dtu
* improved RF24 ISR
* reduced AP active time to 60s (will be increase once a client is connected)
* added `yield` without success -> random reboot (cause 4)
* html / css files are now located inside PROGMEM
* conversion of files is done with python script (OS independent, open source)
* moved as much as possible for now to the hm* modules - the app should only be the body
* successfully tested with HM1200