Do not make absolute paths relative if they aren't under the base

[byteit101]

This only makes paths relative if they are under the base, and does not relativeize those absolute paths.

This caused issues with paths with spaces for xjc. Now paths with spaces work with xjc again (originally broken in 2.4, worked in 2.3.1).

Fixes #131

[patrickptibco]

I have updated this with the latest changes

[tibco-jufernan]

Can this be merged for the next release?

[ratoaq2]

On 4.0.0

    public static String relativize(final String path, final File parentDir, final boolean removeInitialFileSep) {

        // Check sanity
        Validate.notNull(path, "path");
        Validate.notNull(parentDir, "parentDir");

        final Path p = Paths.get(path);
        final Path pd = parentDir.toPath();

        String platformSpecificPath;
        if (p.normalize().startsWith(pd.normalize().toString())) {
            platformSpecificPath = pd.relativize(p).toString();
            if (removeInitialFileSep && platformSpecificPath.startsWith(File.separator)) {
                platformSpecificPath = platformSpecificPath.substring(File.separator.length());
            }
        } else {
            platformSpecificPath = p.toString();
        }

        // NOTE: it appears this function is meant to preserve the file separator that was passed in the path
        if (path.indexOf('\\') == -1) {
            platformSpecificPath = platformSpecificPath.replace('\\', '/');
        }

        return platformSpecificPath;
    }