travis_wait only allows a single command to run for 20 min, but my command is unlikely to finish in 20 min, so let me use a custom version to extend my travis time
travis_wait only allows a single command to run for 20 min, but my command is unlikely to finish in 20 min, so let me use a custom version to extend my travis time

yihui/crandalf,yihui/crandalf