Fix test_reset()

[adbancroft]

This PR combines a number of changes to ultimately have a reliable unit test of ArduinoFakeContext::Reset():

1. Remove all heap allocation - simpler, more reliable and aligns with modern C++ code style ("Always use automatic variables unless you have a compelling reason or requirement not to")
2. Replace behavior in macros with classes - allows for unit testing the behavior (see ProxiedArduinoFake_t and OverrideableProxiedArduinoFake_t)
3. Limit scope of accessor generating macros _ArduinoFakeInstanceGetter1 & _ArduinoFakeInstanceGetter2. Not strictly necessary for the PR but is good practice.
4. Makefile runs verbose tests (not strictly necessary for the PR but useful)
5. Test harness returns number of failing tests, which will cause CTest to fail when tests fail (also not strictly necessary for the PR but useful).

The unit test of ArduinoFakeContext::Reset() tests behavior rather than implementation.

Fixes #80