Constructs a relative path from path from to path to.
If this is not possible (i.e. different drive letters on windows systems),
NA is returned.
getRelativePath(to, from = getwd(), ignore.case = isWindows())[character(1)]: A relative path.
[character(1)]
Where the relative path should point to.
[character(1)]
From which part to start.
Default is getwd.
[logical(1)]
Should path comparisons be made case insensitve?
Default is TRUE on Windows systems and FALSE on other systems.