dynamically set task timeout duration in master

[putcn]

Currently, a task timeout duration is hardcoded as 20min. one improvement we can do is to set this duration dynamically. we can collect this data from the previously finished job and keep monitoring, changing this value.

[gongweibao]

Task timeout is a command-line parameter now:

taskTimeoutDur := flag.Duration("task-timout-dur", 20*time.Minute, "task timout duration.")