Also bump zeroconf to the version used by PIO

* update platformio.ini comments
* espurna-base -> espurna-core-webui
* esp8266-<flavour>-<size>-base -> esp8266-<size>-<flavour>-base
* clean-up ESPURNA_CORE detection, use boards function

* base envs

* CI: speed up release process (since we still want some .bin files)

* fixup! CI: speed up release process (since we still want some .bin files)

* release dry run

* fixup! release dry run

* adjust

* fix .bin name

* it works

* minor cleanup for current git

* use pio suggestion about ldscript, reduce build_flags impact

* fix linker

* parse ${vars} instead of ignoring them

* add filtering and override file (sneak peak into tasmota's pio config)

* don't generate secure client (for now)

* formatting

* codacy

* PIO: remove -ota envs, handle OTA condition in extra script
* Tweak ESPURNA_BOARD variable
* Support git and latest in ota script
* Handle ESPURNA_FLAGS too
* Try to handle env and projenv in pylint
* Add deprecation comment about -ota envs
* regen arduino.h

* use basic sleep instead of busyloop
* print immediately when no sort option is specified, disable default hostname sort
* restructure
* update requirements.txt
* cli timeout arg, increase default timeout to ensure that all devices are found
* use black for formatting
* shorter ifs

* include build_date in mdns (and ota.py)

* ota.py: correct number of dashes in header

- update file paths: .pioenvs -> .pio/build, .piolibdeps -> .pio/libdeps
- modify envs to use common settings
- enable shared libs in travis and ota scripts

* Fix env size formatting
* Windows support for ota.py
* Sort queue by board to speed up compilation
* Safeguard .pioenvs/elfs