Getting very drunk and then driving the wrong way has earned a Dallas woman a conviction for intoxicated manslaughter.  A Collin County jury found Mariza Martinez guilty of causing the crash that killed a Little Elm teenager on the Dallas North Tollway last year.  Investigators determined that Martinez drove the wrong way for at least six miles in Plano and Frisco before smashing head-on into the car carrying 16-year-old Kara Taylor and her best friend who was seriously injured.  The punishment phase of the trial is scheduled to start this morning. Martinez could get up to 20 years