gui: make kinetic scrolling more natural

Speeding up scrolling after releasing is distracting, get rid of it.
Instead reduce friction to its previous value.

Change-Id: I5c99cc71b631747697e967bd75669aa3d908c637
diff --git a/gui/scrolllist.cpp b/gui/scrolllist.cpp
index 9e8db4c..6143b60 100644
--- a/gui/scrolllist.cpp
+++ b/gui/scrolllist.cpp
@@ -27,9 +27,9 @@
 #include "objects.hpp"
 #include "../data.hpp"
 
-const int SCROLLING_SPEED_DECREMENT = 12; // friction
+const int SCROLLING_SPEED_DECREMENT = 6; // friction
 const int SCROLLING_FLOOR = 10;	// minimum pixels for scrolling to start or stop
-const int SCROLLING_MULTIPLIER = 2; // initial speed of kinetic scrolling
+const int SCROLLING_MULTIPLIER = 1; // initial speed of kinetic scrolling
 const float SCROLLING_SPEED_LIMIT = 2.5; // maximum number of items to scroll per update
 
 GUIScrollList::GUIScrollList(xml_node<>* node) : GUIObject(node)