Fix application name

Author: rbuj

help/C/complex.page

@@ -9,6 +9,6 @@
 	<title>Complex Numbers</title>
 
     <p>
-    Complex numbers are not supported in <app>GCalctool</app>.
+    Complex numbers are not supported in <app>MATE Calculator</app>.
     </p>
 </page>

help/C/functions.page

@@ -86,6 +86,6 @@
     </tr>
     </table>
     <p>
-    <app>GCalctool</app> does not support user-defined functions.
+    <app>MATE Calculator</app> does not support user-defined functions.
     </p>
 </page>

help/C/index.page

@@ -10,7 +10,7 @@
 		<include href="legal.xml" xmlns="http://www.w3.org/2001/XInclude" />
 	</info>
 
-	<title>GCalctool Help</title>
+	<title>MATE Calculator Help</title>
 
     <section id="ui" style="2column">
         <title>User Interface</title>