willvincent's sandbox: Search Exclusion

This module will add an additional setting to node edit forms (in the vertical tabs area) allowing specific nodes to be excluded from search.

It seems to work pretty well, and the DB schema is set up such that it will ultimately be able to handle other entity types besides nodes, though code for other entity types isn't implemented currently.

Also, it seems that it doesn't prevent items from being added to the index, just prevents them from being displayed as results for a search. While that works, and gives the desired end effect, it seems it would be better to prevent indexing in the first place -- not sure if that's possible. If anyone has information on how I would accomplish that it would be most helpful.