Added xml UI for the avfilter.epx

data/effects/avfilter/avfilter_epx.xml

+<!DOCTYPE kpartgui>
+<effect tag="avfilter.epx" id="avfilter.epx">
+	<name>EPX Scaler</name>
+	<description>Scale the input using EPX algorithm.</description>
+	<author>libavfilter</author>
+    <parameter type="list" name="av.n" default="3" paramlist="2;3">
+        <paramlistdisplay>2x,3x</paramlistdisplay>
+        <name>Scale factor</name>
+    </parameter>
+</effect>