GUI: Use valid XML syntax

Safer handling:
& --> &
> --> >
< --> &lt;

Broken tags:
</function>      --> </action>
<folders="1"...> --> <filter folders="1"...>

Change-Id: Iaddaf9db163e08250cb4deefdfdb814c589ccb47
diff --git a/gui/devices/540x960/res/ui.xml b/gui/devices/540x960/res/ui.xml
index 5abe640..673d810 100644
--- a/gui/devices/540x960/res/ui.xml
+++ b/gui/devices/540x960/res/ui.xml
@@ -236,8 +236,8 @@
 				<placement x="200" y="70" />
 				<conditions>
 					<condition var1="tw_no_battery_percent" var2="0" />
-					<condition var1="tw_battery" op=">" var2="0" />
-					<condition var1="tw_battery" op="<" var2="101" />
+					<condition var1="tw_battery" op="&gt;" var2="0" />
+					<condition var1="tw_battery" op="&lt;" var2="101" />
 				</conditions>
 				<text>Battery: %tw_battery%</text>
 			</object>
@@ -397,7 +397,7 @@
 				<layout3>
 					<keysize height="78" width="54" />
 					<row1 key01="1" key02="2" key03="3" key04="4" key05="5" key06="6" key07="7" key08="8" key09="9" key10="0" />
-					<row2 key01="@" key02="#" key03="$" key04="%" key05="&" key06="*" key07="-" key08="+" key09="(" key10=")" />
+					<row2 key01="@" key02="#" key03="$" key04="%" key05="&amp;" key06="*" key07="-" key08="+" key09="(" key10=")" />
 					<row3 key01="81:layout4" key02="!" key03="54:c:34" key04="'" key05=":" key06=";" key07="/" key08="?" key09="81:c:8" />
 					<row4 key01="81:layout1" key02="54:," key03="270: " key04="54:." key05="81:action" />
 				</layout3>
@@ -405,7 +405,7 @@
 					<keysize height="78" width="54" />
 					<row1 key01="~" key02="`" key03="|" key04="54:" key05="54:" key06="54:" key07="%" key08="54:" key09="{" key10="}" />
 					<row2 key01="54:" key02="54:" key03="54:" key04="54:" key05="54:" key06="^" key07="_" key08="=" key09="[" key10="]" />
-					<row3 key01="81:layout3" key02="54:" key03="54:" key04="54:" key05="54:" key06="\" key07="<" key08=">" key09="81:c:8" />
+					<row3 key01="81:layout3" key02="54:" key03="54:" key04="54:" key05="54:" key06="\" key07="&lt;" key08="&gt;" key09="81:c:8" />
 					<row4 key01="81:layout1" key02="54:c:34" key03="270: " key04="54:." key05="81:action" />
 				</layout4>
 			</object>