[Fixes #246] Don't run file tasks needlessly

[grzuy]

This PR:

• Fixes issue Rake executes file task when prerequisites have older timestamp #246 by reverting PR FileTask#out_of_date? calls depended FileTask#out_of_date? for execution #183, which was attempting to fix issue Rake -n does not mark dependents for Execution #92, which it seems to me not an actual issue. See comment Rake -n does not mark dependents for Execution #92 (comment).

[hsbt]

I'm not sure why your specification was correct behavior. I will continue to see watch #92.

[grzuy]

Thanks @hsbt

Were you able to see comments in #92?
Do you have any opinion about it?

[grzuy]

Hi @hsbt

There hasn't been an agreement on issue #92 yet, so in order to move forward i opened a new PR #257, that replaces this one, which still fixes issue #246 but with a different approach that keeps requested behavior in issue #92, instead of reverting it.