WTI oil prices continue to flirt with the $100 level. The Houston Ship Channel saga both boosted prices and dragged them down, as the situation waxed and waned, yesterday. At one point, the Coast Guard sounded a lot more like the EPA than the maritime police in suggesting its overarching concern about the state of the oil spill, at the expense of shipping interests. Then, later in the day, the channel was opened to outbound traffic,