Crude oil prices on Thursday settled at the highest in six months, with Brent crude topping $71 per barrel and WTI over $66. However, this may be just the start of a much stronger rally—it all depends on developments between the United States and Iran. The latest round of negotiations between the two on Iran’s nuclear program started well enough, with both sides signaling they wanted to make a deal. Iran’s Foreign Minister signaled there was progress being made, saying the negotiating teams had agreed on “guiding principles.”…