Fix #1207: Add Batch scripts and improve Shell scripts

[floating-cat]

No description provided.

[dottybot]

Hello, and thank you for opening this PR! 🎉

All contributors have signed the CLA, thank you! ❤️

Have an awesome day! ☀️

[floating-cat]

retest this please

[smarter]

Hi @floating-cat and thanks for the PR! I don't think there's any way to redo the CLA check on the PR, but that's OK, I've manually checked on https://www.lightbend.com/contribute/cla/scala/check/floating-cat that you have signed the CLA.

[floating-cat]

Thanks. This pull request is ready for review.
Though I am not sure who would like to review.

[allanrenucci]

I think #1207 refers to windows version of dist/{dotc, dotd, dotr}.

Also, I think a better solution here is to get rid of the project/scripts/build/... scripts and reimplement project/VersionUtil.scala using JGit. You can look at what scalac does: https://github.com/scala/scala/blob/2.13.x/project/VersionUtil.scala#L55-L86

[floating-cat]

You are right, reimplement VersionUtil using JGit is better.
So I close this PR. If I have time to redone this, I would open a new PR.