Add jobby output to console log

[mgbolivierdahinden]

For some time I was in need to use jobby with console output. Since
we are working in cloud foundry environment and we capture application
log with a drainlog this was quite critical.

This commit introduces the config flag output_console which takes
a boolean to either activate the output to console. What it actually
does is remove the bash output to logs and puts an echo infront of
the exec().

While at it: Add composer script for tests. Add 2 testcases for
closures and files.

[mgbolivierdahinden]

I'm sure this is not yet ready since it's not that clean. But maybe it is inspiring and maybe bringing another solution from you guys.