Improve display of VTs

For every displayed canonical Title, the software will do the following:

1. Check if the Title has any VTs. If not, move to the next non-VT Title.
2. Check whether the canonical Title has no pubs directly associated with it (not counting any pubs associated with its VTs). This information will be used in subsequent steps.
3. Check if the Title has more than one VT, in which case display the VTs on subsequent lines. If the canonical Title has no pubs (see Step 2), then also print "only appeared as:" on the canonical Title's line. If the canonical Title has pubs, print "also appeared as:". Move on.
4. We are here if there is a single VT. Check if the VT is spelled the same as the canonical Title. If it is, move to the next step for this Title. If it is not, display the VT on a separate line. If the canonical Title has no pubs (see Step 2), then also print "only as:" on the canonical Title's line. Move on.
5. We are here if there is a single VT and it is spelled the same way as the canonical VT. If there is at least one pub for the canonical Title (see Step 2), display "[also as by]" on the same line and move on.
6. Otherwise display the VT using the "[as by ...]" convention on the same line as the canonical Title.