Avoid releasing too often / too little

There's no need to have a release for just one commit (for example if there's a cronjob running the day after a manual release).

• A maxCommit option (currently: 1) would define how many commits are needed for a new release.
• A maxAge option (currently: 0) would define how many days a commit can wait to be released.

These 2 options complement each other. For example, "don't release 2 commits unless they've already been pushed 5 days ago"

However I think that there should be a way to skip this logic. Maybe manual releases can automatically be detected.