* Boko Haram shoot and burn students
* Islamists have killed more than 300 this month
* Nigerian military under fire for not protecting civilians
By Joe Hemba
DAMATURU, Nigeria, Feb 25 (Reuters) - Gunmen from Islamist group Boko Haram shot or burned to death 59 pupils in a boarding school in northeast Nigeria overnight, a hospital official and security forces said on Tuesday....