Added xml UI for the avfilter.monochrome

data/effects/avfilter/avfilter_monochrome.xml

+<!DOCTYPE kpartgui>
+<effect tag="avfilter.monochrome" id="avfilter.monochrome">
+	<name>Monochrome</name>
+	<description>Convert video to gray using custom color filter.</description>
+	<author>libavfilter</author>
+	<parameter type="animated" name="av.cb" default="0" min="-1" max="1" decimals="3">
+                <name>Chroma blue spot</name>
+        </parameter>
+        <parameter type="animated" name="av.cr" default="0" min="-1" max="1" decimals="3">
+                <name>Chroma red spot</name>
+        </parameter>
+        <parameter type="animated" name="av.size" default="1" min="0.1" max="10" decimals="3">
+                <name>Color filter size</name>
+        </parameter>
+        <parameter type="animated" name="av.high" default="0" min="0" max="1" decimals="3">
+                <name>Highlights strength</name>
+        </parameter>
+</effect>