fast finish travis
remove 1.9.2 and ree from travis
use rubies 2.0 and 2.1 instead of 2.0.0
try mac travis
recreate kill_children without calling children_pids (Sys::ProcTable.ps) from thread

Calling Sys::ProcTable.ps from thread using ruby1.9 on mac causes «SystemStackError: stack level too deep» djberg96/sys-proctable#36