Remove duplicate app icon

Use the 64px application icon available in tools/icon instead of the
copy in resources.

Adapt the Qt resource file to use the new path, keeping the old name
for compatibility.

leocad.pro

@@ -131,7 +131,7 @@ unix:!macx {
 	desktop.path = $$DESKTOP_DIR
 	desktop.files = qt/leocad.desktop
 	icon.path = $$ICON_DIR
-	icon.files = resources/leocad.png
+	icon.files = tools/icon/64x64/apps/leocad.png
 	mime.path = $$MIME_DIR
 	mime.files = qt/leocad.xml
 	mime_icon.path = $$MIME_ICON_DIR

leocad.qrc

@@ -78,7 +78,7 @@
         <file>resources/time_next.png</file>
         <file>resources/time_previous.png</file>
         <file>resources/time_stop.png</file>
-        <file>resources/leocad.png</file>
+        <file alias="resources/leocad.png">tools/icon/64x64/apps/leocad.png</file>
         <file>resources/help_homepage.png</file>
         <file>resources/view_zoomextents.png</file>
         <file>resources/view_split_horizontal.png</file>