Reviewed by GREG KING Documentary Director: T C Johnstone. In 1994 the African country of Rwanda endured a savage and violent episode of "ethnic cleansing" that killed 20% of the population. The horrific genocide killed nearly one million people over the course of three months and devastated the country. In 2005, Tom Ritchey, one of the developers of the mountain bike, discovered the joys of cycling Rwanda, …