Stopped supported -0 as a float output because (a) it is non-portable, only existing on some architectures and (b) relies on the undefined behavior of 1.0/0.0

- fixed ANSI (C89) issues, including #418

Converting RUN_TEST() from a macro to a function significantly reduces the size
of the compiled binary.  On amd64, the largest test runner in the test suite
(testsample_DefaultsThroughCommandLine_runner.o) was reduced from 3.4 kB to 2.4
kB (stripped).

Add TEST_MESSAGE for outputting messages without aborting a test and _MESSAGE variant to TEST_PASS collection.

- Running time macros have been made more portable, previously it was not
  possible to override all macros
- Running time macros will be executed by default test runner, and auto test
  runners
- Adds a default execution time implementation for unix. (Previous default
  implementation only worked on Windows)
- For embedded platforms there is a simple method of getting a default
  implementation by defining a single macro UNITY_CLOCK_MS()
- Removed need for UNITY_EXEC_TIME_RESET. This was not being used for the default
  implementations, if anything ever did need reset-like functionality it could
  simply be wrapped up with the start or stop macros for that platform

 void flushSpy(int c) {}
to:
 void flushSpy(void) {}

The existing implementation was not very good:
 - It printed all very small values as "0.000000..."
 - It did not distinguish positive and negative zero
 - In some cases it printed extra garbage digits for single-precision values
   (e.g. 3.9e+30 was printed as 3.90000013+30)

Tests have been updated to check that we now match printf("%.6g") for
1,000,000 randomly chosen values, except for rounding of the 6th digit.

Starting to enforce our coding style. The first step is that we’ve pulled in Rubocop to check out Ruby syntax. There is likely a bit of customization to do yet AND there is definitely that backlog of todo’s that we just told it to ignore.

Correct clean target and print test fails during coverage in Makefile

Using this option changes the control flow of Unity, but is useful on
constrained embedded systems. You can't fully simulate the power of
'longjmp' with just 'return', but Unity still works well, all tests pass.

Originated from commit c6dc96f3 but are rarely used and not in math.h
Removes float to double promotion warning and simplifies the code
'gcc -std=gnu99 -Wdouble-promotion' spits out these warnings