#299 Stack-overflow when processing pbm images

[Hongxu Chen]

As of git commit 23522feec1e200cd2981c8e063ce1ea3a333a14f (DjVuLibre-3.5.27), running cjb2 $FILE /dev/null may trigger a stack-overflow error at GContainer.h:557 which results from a recursive call to GArrayTemplate<Run>::sort.

[Leon Bottou]

fixed