Thunderbird full-text search prototype a la SQLite FTS3

Full-text search using FTS3.

Full-text search with a contact constraint.

The global database sqlite file resulting from indexing all of mozilla.dev.apps.thunderbird is about 13M for something like 4500 messages.  We’re providing FTS3 with the bodies (but not attachments!) of all the newsgroup messages and the subjects of the messages which initiate new threads.  For real usage, we will need to also index the subjects of each message.

Note that the message bodies have not been processed at all by the Thunderbird/gloda code before handing them off to FTS3.  So quoted messages get indexed even though it’s a lot of excess data.  We’re relying on FTS3 to do all stop-words, etc.  FTS3’s Porter stemming/tokenization is in use.