Fixes local source path escaping

[skolima]

No description provided.

[skolima]

Related to #386

[AnthonySteele]

ArgumentEscaper.EscapeAndConcatenate looks useful, but what is actually going wrong with adding " quotes? Are some of the args already IsSurroundedWithQuotes ?

Or is it bad to add quotes when they aren't needed (i.e. no actual spaces in the path)?

[skolima]

I was adding a) quotes where they weren't required (see the updated test - there's no need to quote the first source) and b) not escaping the \ where it was required (thus the source C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\ was failing. CMD.exe is odd in that \ only needs to be escaped sometimes. Fun!

[AnthonySteele]

Ah, so a was not fatal but b was. Well spotted! and good that someone already has code to do the right thing with it!