Greatly enhanced install-symlinks.

Now reminiscent of a full operating system, links are installed with
care and trepidation.

Most links are installed with the function `link', which acts as
follows.

$1 is the source file
$2 is the destination file
$3 (optional) is the parent folder that needs to exist for $2 to exist

Root files are handled in their own space

Finally, unnecessary double quotes were removed