Add a Copy/Paste file function

[skimania]

I'd like to stop using SideBarEnhancements, but the one function I use there very often is Copy/Paste of files and folders. I tend to do this across different open sublime windows/projects, like copy a directory from one and paste it elsewhere. I know you have the "duplicate" function, but then you have to type in the path, and they're long and that's just not sufficient for me. Thanks.