Add support to run job NOW AND LATER instead of just LATER

[opslock-benjamin]

After reading the docs I couldn't find a way to run crons now as soon as i start , and then later at the next interval.

Is there a way to do this currently?

If not I think its a worthy feature to test code easier instead of modifying 1000 registered functions to run every 1 second

[zeewell]

#436

[alaingilbert]

@opslock-benjamin I made a fork of this repo that addresses almost all issues of this repo.
https://github.com/alaingilbert/cron

This is how you could do what you want to do ->

_, _ = c.AddJob("*/10 * * * * *", func() {
    fmt.Println("this job runs as soon as cron is started, then at every 10th seconds", time.Now())
}, cron.RunOnStart)