CWD Tilde handling

[vyeevani]

Not sure if this is necessary a feature or just a fix for some so I'll classify it as a feature for now. Fail to find "lldb-mi" when the cwd has a "~" expansion in it.

[vyeevani]

According to this, the child process developers rejected handling cwd tilde expansion so it would have to be handled inside this repo: nodejs/node#684

[GitMensch]

The feature implementation like that sounds easy:

cwd = cwd.replace(/^~/, os.homedir());

But I think this then may also be applied not to cwd, but also to the program and gdb/lldb executable and the argument list - if those don't work already.

[vyeevani]

I’ve made this PR to resolve this with untildify so that the support isn’t hard coded here as a string replacement. #288

[vyeevani]

@GitMensch do you happen to have write access to get this merged?

[GitMensch]

@vyeevani yes, but I won't do it now as @WebFreak001 had more or less the same questions that I had, please see the PR comments.