depends_on_formula for containers really needed?

[muescha]

a follow up from #2744:

@muescha if you are curious about
how the design decisions were reached,
you may refer to #1992 and #2305 .

ok - its a design decition

but:

1. only for 'find casks using this formula' you force to add the depends_on_formula on each casks while you can determinate it easy anyway?

2. the request from @phinze was in add dependencies for Homebrew formulae #2305:

not to add depends_on stanzas to brew-cask.rb,
but to defer dependencies until install-time for individual Casks

this is also satisfied if the depends_on_formula are filled (or executed) at the container while the me? check - then its done at install-time

[rolandwalker]

Thanks for your input! Closing as duplicate of #2305.