Switch from Float to Integer Time Values

- Use fast data types where possible so the compiler can optimize for speed based on platform
    - for example, 128 bits might be fastest on ARM
    - good future-proofing

- Refactor GetTimeSinceStart() to be a bit faster
    - multiplication is much faster than division

- Implement a RageTimer method to get the seconds value as a plain int, for the places which cast the seconds value to an int

- Changing from GetTimeSinceStartFast() to GetTimeSinceStart() where accuracy is important

- Changing from GetTimeSinceStart() to GetUsecsSinceStart() for timestamp diffs

- Adjust RageThreads to accomodate an unsigned timestamp value
   - a constant for the maximum value of `uint_fast64_t` replaces `-1` to accommodate the change from signed to unsigned for the `locked_at` variable
   - i have separate constants for `std::numeric_limits<std::uint_fast64_t>::max()` and `static_cast<std::uint_fast64_t>(-1)`, so the reader understands -1 represents an error code, though they evaluate to the same value, so i could remove one of the two

- Add two methods to calculate the MMSSMsMs / MMSSMsMsMs time value from usecs directly instead of inferring it from a seconds value, in RageUtil

- Use a similar counter/modulo based method for WheelNotifyIcon, similar to what i did for text_glow in NoteField in 2eeee03

- Make `g_iStartTime` static const for safety

Rename two timer functions:
GetUsecsSinceStart -> GetTimeSinceStartMicroseconds
GetMicrosecondsSinceStart -> GetSystemTimeAsMicroseconds

Remove std prefix from uint_fast64_t

src/ArrowEffects.cpp

@@ -101,13 +101,13 @@ float ArrowEffects::GetTime()
 	{
 	    case ModTimerType_Default:
 	    case ModTimerType_Game:
-		return (RageTimer::GetTimeSinceStartFast()+offset)*mult;
+		return (RageTimer::GetTimeSinceStart()+offset)*mult;
 	    case ModTimerType_Beat:
 		return (GAMESTATE->m_Position.m_fSongBeatVisible+offset)*mult;
 	    case ModTimerType_Song:
 		return (GAMESTATE->m_Position.m_fMusicSeconds+offset)*mult;
 	    default:
-		return RageTimer::GetTimeSinceStartFast()+offset;
+		return RageTimer::GetTimeSinceStart()+offset;
 	}
 }
 
@@ -316,7 +316,7 @@ void ArrowEffects::Init(PlayerNumber pn)
 void ArrowEffects::Update()
 {
 	static float fLastTime = 0;
-	float fTime = RageTimer::GetTimeSinceStartFast();
+	float fTime = RageTimer::GetTimeSinceStart();
 
 	FOREACH_EnabledPlayer( pn )
 	{