Game/FPSCounter: change m_fps variable and getFPS() return value from float to double.

MSVC complains about loss of information because sp::Time::seconds() returns double.

include/Spectre/Game/FPSCounter.h

@@ -17,7 +17,7 @@ public :
 	// Should be called whenever a frame has been rendered.
 	void addFrame();
 
-	float getFPS() const;
+	double getFPS() const;
 
 	// Set the update rate (in seconds).
 	// How often the FPS should be sampled and calculated.
@@ -42,7 +42,7 @@ private :
 	Time m_updateRate;
 
 	// Calculated Frames per second.
-	float m_fps;
+	double m_fps;
 };
 
 } // namespace sp

source/Game/FPSCounter.cpp

@@ -16,7 +16,7 @@ void FPSCounter::addFrame()
 	m_count++;
 }
 
-float FPSCounter::getFPS() const
+double FPSCounter::getFPS() const
 {
 	return m_fps;
 }