Introduced custom application launch text

This can be used to override weird automatically constructed messages
such as "Launching Power Off".

data/platform/gcw0/sections/settings/10_poweroff

@@ -1,5 +1,6 @@
 title=Power Off
 description=Shut down the system
+launchmsg=Powering off
 icon=skin:icons/poweroff.png
 exec=/sbin/poweroff
 editable=false

data/platform/gcw0/sections/settings/20_reboot

@@ -1,5 +1,6 @@
 title=Reboot
 description=Reboot the system
+launchmsg=Rebooting
 icon=skin:icons/reboot.png
 exec=/sbin/reboot
 editable=false