Part of DCist’s continuing coverage of Deluge ’06. When you headed out in your car yesterday, you probably felt a bit like Noah boarding the ark. You checked your two headlights, two windshield wipers, two pairs of shoes, and, if you were Rush Limbaugh, two Viagra. As the rain takes a breather, let’s learn about two D.C. cases involving flood victims that, together, will be necessary for anyone considering suing the city when the…