depends: find-like output

when dealing with package dependency woes, such as

http://cygwin.com/ml/cygwin/2014-10/msg00563.html

The current "depends" tree method fails, because it only shows the packages, not
the dependency paths. These paths are necessary to solve the "shortest path
problem"

http://wikipedia.org/wiki/Shortest_path_problem

Now, every possible dependency path will print from the chosen package. Combined
with category search you can run searches such as

    apt-cyg category Base |
    apt-cyg depends |
    awk '/perl$/ {print length,$0}' |
    sort -n

Solving the path problem in seconds.