DomoticsCore v2.12.1

On ESP8266, local time now follows the configured timezone. It never
did: the SNTP client was started with configTime(0, 0, ...), which resets
the C library's zone to GMT, so every ESP8266 ran on UTC whatever the
timezone, DST included. After updating, an ESP8266 configured for Paris
reads two hours later in summer. getUnixTime() is unchanged.

Fixed

• NTPComponent::getGMTOffset() and getISO8601() were an hour short during
  DST on every platform (14:00+01:00 for 14:00 CEST); an offset under an
  hour west of UTC printed as positive (+00:30 for -00:30).
• Shortening the NTP server list no longer leaves the removed servers polled.
• Configuring more than three NTP servers logs a warning: the client uses three.
• library.properties declares its dependencies and carries the release's
  version; it had stayed at 2.0.0.

Changed

• Tests: the native heap measurements no longer count glibc's tcache or the
  tracker's own checkpoints, and native suites run through env, so on Linux
  and macOS hosts only.