Improvements to the execution time feature

- 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

src/unity.c

@@ -599,7 +599,7 @@ void UnityConcludeTest(void)
 
     Unity.CurrentTestFailed = 0;
     Unity.CurrentTestIgnored = 0;
-    UNITY_EXEC_TIME_RESET();
+    UNITY_PRINT_EXEC_TIME();
     UNITY_PRINT_EOL();
     UNITY_FLUSH_CALL();
 }
@@ -1589,6 +1589,7 @@ void UnityDefaultTestRun(UnityTestFunction Func, const char* FuncName, const int
     Unity.CurrentTestLineNumber = (UNITY_LINE_TYPE)FuncLineNum;
     Unity.NumberOfTests++;
     UNITY_CLR_DETAILS();
+    UNITY_EXEC_TIME_START();
     if (TEST_PROTECT())
     {
         setUp();
@@ -1598,6 +1599,7 @@ void UnityDefaultTestRun(UnityTestFunction Func, const char* FuncName, const int
     {
         tearDown();
     }
+    UNITY_EXEC_TIME_STOP();
     UnityConcludeTest();
 }
 
@@ -1612,7 +1614,6 @@ void UnityBegin(const char* filename)
     Unity.TestIgnores = 0;
     Unity.CurrentTestFailed = 0;
     Unity.CurrentTestIgnored = 0;
-    UNITY_EXEC_TIME_RESET();
 
     UNITY_CLR_DETAILS();
     UNITY_OUTPUT_START();