Handle powershell tilde expansion

[andren]

Addresses #53

Before

See issue above

After

Made it case-insensitive and used regex to account for drive letters other than C.

[andren]

I only noticed now, latest commit addresses the wrong text output.

before
Export spaces C:\Users\347_____________________________ at ____-__-__ __:__:__

after
Export spaces ~347_____________________________ at ____-__-__ __:__:__

It still worked, but it was misleading text.

[Spenhouet]

@andren Is this PR ready from your side?

[andren]

@Spenhouet yes, I tested right before my last comment. I didn't notice any additional flaws in the meantime.

The only breaking scenario I can imagine, is if someone has a Confluence space whose name starts with C:\Users\, z:\users\ or any other drive letter, case-insensitive. In this case, cf-exporter might wrongly replace that with a tilde, but I haven't tested this yet.