v1.4.0 - add optional setupCoroutine() to Coroutine class

• 1.4.0 (2021-07-29)
  • Upgrade STM32duino Core from 1.9.0 to 2.0.0.
    • MemoryBenchmark: Flash usage increases by 2.3kB across the board, but
      static RAM goes down by 250 bytes. Very little change to AceRoutine
      code itself.
    • AutoBenchmark: No change.
  • Upgrade SparkFun SAMD Core from 1.8.1 to 1.8.3.
    • No change observed in MemoryBenchmark or AutoBenchmark.
  • Add virtual Coroutine::setupCoroutine() with a default empty
    implementation, and optional CoroutineScheduler::setupCoroutines() to
    automatically loop over all coroutines.
    • See Issue #36 for
      motivation.
    • If not used, Coroutine::setupCoroutine() increases flash consumption
      by 4 bytes, and static memory by 2 bytes per coroutine on AVR
      processors.
    • If used, Coroutine::setupCoroutine() can consume a significant
      amount of memory resources. On AVR, at least 50-60 bytes per
      coroutine. On 32-bit processors, about 30-40 bytes per coroutine.