* Somalia battling stubborn al Shabaab insurgency
* Rebels have staged high-profile attacks in capital
* Government wants residents to inform on militants
By Drazen Jorgic
MOGADISHU, April 16 (Reuters) - When Islamist militants blasted their way to within 50 metres of the Somali president's residence, they forced a sharp rethink of security in the capital Mogadishu.
The deadly ...