Fixed: Support Windows #30

[jsinger67]

• replaced touch in windows context with copy nul file.txt
• replaced grep with regex::Regex
• replaced xargs by giving multiple branch names to `git branch -d/-D'
• tested on Windows and WSL Ubuntu

[mcasper]

Thanks for this @jsinger67! I don't have a Windows machine set up for development, so I'll just take your word that it works 😄 Looks good on Mac

[jsinger67]

Ok, fine 👍 I use it regularly here on my Windows machine and it works flawlessly! Feel free to assign possible bugs regarding my changes to me.