Fixed issue when calculating significant, if marker_count is 0 there is a divide by zero error
Fixed issue when calculating significant, if marker_count is 0 there is a divide by zero error

jbcden/gruff,topfunky/gruff,innoq/gruff,vigetlabs/gruff,philipgiuliani/gruff,iox/gruff,MentalPower/gruff,house9/gruff,topfunky/gruff,isozaki/gruff,jrmhaig/gruff