TextButtonList working kinematic background

Former-commit-id: 8976d3b3d1e40731adf13430ad747351a6401b24

src/net/torvald/terrarum/ui/UIUtils.kt

@@ -0,0 +1,11 @@
+package net.torvald.terrarum.ui
+
+import net.torvald.terrarum.gameactors.sqr
+
+/**
+ * Created by SKYHi14 on 2017-03-14.
+ */
+object UIUtils {
+    fun moveQuick(start: Double, end: Double, timer: Double, duration: Double) =
+            (start - end) * ((timer / duration) - 1).sqr() + end
+}