fallback for when no tiddler exists.
fallback for when no tiddler exists.

When slices are used sometimes a tiddler object is not passed down to the handler.
Since the tiddler is only used to get the adaptor I put some fallback in to prevent
this breaking the plugin.

FND/tiddlyspace,FND/tiddlyspace,TiddlySpace/tiddlyspace,TiddlySpace/tiddlyspace,FND/tiddlyspace,TiddlySpace/tiddlyspace