Add option for fast search

[belozer]

Add option for fast search

[qfox]

what about content and input?

upd: ah, you asking for one level look, it would not be fast for current realization because it reads full graph before going to walk through nodes. No sense to prevent walking through nodes in memory for speed, but probably it's needed to find direct dependents

[belozer]

@zxqfox In General, it is adjacent to #6

[belozer]

The current implementation is cool, which displays all side effects. But sometimes you need to get more accurate information.