v0.8 - merge ESP8266 compatibility code from EspMock into EpoxyDuino

• 0.8 (2021-08-08)
  • Add EpoxyMockTimerOne mock library for TimerOne
    (https://github.com/PaulStoffregen/TimerOne).
  • Add library.json to support
    PlaformIO in Native
    mode. (See
    PR #31 by
    https://github.com/lopsided98).
  • Move code that pumps the Serial object from unixhostduino_main()
    to yield(). Fix bug to allow correct handling of NUL byte in the
    serial stream. (See [PR #32] by https://github.com/lopsided98).
  • Breaking Repurpose the EPOXY_CORE make variable to be the name of
    the macro that defines the target architecture so that Arduino.h brings
    in definitions which target specific Arduino platforms:
    • The valid options are:
      • EPOXY_CORE_AVR (default)
      • EPOXY_CORE_ESP8266
    • Merge ESP8266-specific changes from
      https://github.com/hsaturn/EspMock/cores/esp8266 into
      EpoxyDuino/cores/epoxy, guarded by EPOXY_CORE_ESP8266 macro.
  • Add map(), makeWord() functions to WMath.cpp.