Run pre and post commands

[MikeDevice]

Command npm run <script> runs pre script, then script and then post script, but nrun don't.

Example

Scripts

{
  "pretest": "echo pretest",
  "test": "echo test",
  "posttest": "echo posttest"
}

nrun test will print only test
npm run test will print pretest, test, posttest

[okv]

That's absolutely true.
I don't know what to say, except "pr's are welcome" =)

[okv]

#5 merged, now it's supported