BBC: BP has delayed a key test on a newly installed well cap aimed at stopping the flow of oil in the Gulf of Mexico. BP and US Coast Guard officials said further analysis was needed before pressure testing could begin. If it proves successful, the well will be kept “shut in” and the leak halted until relief wells plug it entirely. The blown-out well has been spewing oil into Gulf waters since April. The US administration has sent BP and other parties a new bill for the …