gui: Make framerate configurable

Default framerate is 30 FPS

Change-Id: Ia05357663905a3babecb95b1e3531ae45fc854c5
diff --git a/gui/animation.cpp b/gui/animation.cpp
index ed32da4..e8bbd2d 100644
--- a/gui/animation.cpp
+++ b/gui/animation.cpp
@@ -126,7 +126,7 @@
 	if (mLoop == -2)		return 0;
 
 	// Determine if we need the next frame yet...
-	if (++mUpdateCount > 30 / mFPS)
+	if (++mUpdateCount > TW_FRAMERATE / mFPS)
 	{
 		mUpdateCount = 0;
 		if (++mFrame >= mAnimation->GetResourceCount())