In Adafruit_GFX.cpp, variables currstate and laststate are not initialized

[mitchb1]

• Arduino board: Mega2560

• Arduino IDE version (found in Arduino -> About Arduino menu): CLion/PlatformIO

• List the steps to reproduce the problem below (if possible attach a sketch or
  copy the sketch code in too):

In Adafruit_GFX.cpp, variables currstate and laststate are not initialized. This can cause incorrect results from functions justPressed and justReleased.