MicroCore v2.0.0

This release introduces some breaking changes.

Changelog:

• Fix issue where delay(0) didn't work as expected (#115)
• Fix export compiled binary on Windows computers
• Improve "unsafe" macros
  • This includes abs(), min(), max(), sq(), round() and constrain()
• Add PIN macros
  • You can use PIN_PB0 to refer to pins
• Add analog_pin_t typedef enum to refer to analog pins
  • This is a breaking change, and throws an error if you pass anything else than A0, A1, A2, or A3 to analogRead().
• Require pins to be constants, and thus known at compile time
  • This is also necessary, but breaking a change to improve code execution speed and reduce the overall compiled size.