Add: Smooth Scrolling

Rather than embodying the softness itself

Make it feel like follows:
- Slightly fast
- low latency
- Be honest

I don't want too many modifications.

user.js

@@ -23,3 +23,9 @@ user_pref("browser.urlbar.suggest.calculator", true);
 
 // Integrated unit convertor at urlbar
 // user_pref("browser.urlbar.unitConversion.enabled", true);
+
+// ** Scrolling Options ********************************************************
+user_pref("mousewheel.min_line_scroll_amount",               10); /* Original: 5    */
+user_pref("general.smoothScroll.mouseWheel.durationMinMS",   80); /* Original: 50   */
+user_pref("general.smoothScroll.currentVelocityWeighting", 0.15); /* Original: 0.25 */
+user_pref("general.smoothScroll.stopDecelerationWeighting", 0.6); /* Original: 0.4  */