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- support definition of group tasks using basename without any task
- added task property `watch` to specific extra files/folders in auto command
- CmdAction support for all arguments of subprocess.Popen, but stdout and stderr
- added command option `-k` as short for `--seek-file`
- task action can be specified as a list of strings (executed using subprocess.Popen shell=False)
- fix 60: result of calc_dep only considered if not run yet
- fix 61: test failures involving DBM
- fix: do not allow duplicate task names