By Tanner Garrity Before a flight to London last week, I packed the usual essentials in my toiletry bag: toothbrush, contacts, deodorant and a small Ziploc bag filled with a mix of pills — some blue, some white. The blue caplets were Advil PM, which contain diphenhydramine, while the white caplets were three milligrams of melatonin apiece. I pop either, from time to time, as an emergency sleep-aid. In my overpacking tradition, I indiscriminately brought both. I bring tablets along any time I have a long, overnight flight or am somewhat worried about jet-lag fussing with my sleep on important t…