Move the Timer::sleep implementation up from timer/sdl/Timer.cpp to timer/Timer.cpp, since it doesn't directly use any SDL-specific code.

src/modules/timer/Timer.cpp

@@ -21,6 +21,7 @@
 // LOVE
 #include "common/config.h"
 #include "common/int.h"
+#include "common/delay.h"
 #include "Timer.h"
 
 #if defined(LOVE_WINDOWS)
@@ -85,6 +86,12 @@ void Timer::step()
 	}
 }
 
+void Timer::sleep(double seconds) const
+{
+	if (seconds > 0)
+		love::sleep((unsigned int)(seconds*1000));
+}
+
 double Timer::getDelta() const
 {
 	return dt;