new command line option: -repeat

[nubunto]

Recently I've had a freelance opportunity to code, in Go, a small utility that sent a bulk load of copies of the same email to a number of persons repeatedly.

If I had found postman earlier and closed the deal and made the freelance, I surely would have used it. But what about a -repeat command line config? Very simple: it would wrap the .csv file N times.

I'm willing to make a pull request with the feature.