Revert incorrect refreshing of tiddler widget

Mistakenly, I had changed the tiddler widget to refresh itself when the
value of the target tiddler changed. This is not in fact necessary; it
only needs to refresh itself when the identity of the target tiddler
changes.

Fixes #744
Fix tiddler info default tab

Mistakenly omitted from b437f1b450f5f2a3104a9086f7c674299b53b9bc