FORGE-93 Return correct qualified path on Windows

The fix was to ensure that File.separator was added only if absent at the end of the path string. This ensured that Windows paths are not of the form C:\\foo\bar.... despite the use of File.separator when constructing the path.

Also corrected the manner in which the prompt displayed, since the entire path was displayed on Windows due to the above described fix.

And finally, implemented File.separator as the capture target, thus preventing inputs from being lost unless '/' was used, which is unlikely on Windows.

Also incidentally fixed an issue related to FORGE-554 involving relative paths. The earlier fix only resolved the issue involving absolute paths.