Possible to create whitespace tiddler titles

[jdlrobson]

This only concerns plugins. If a plugin for instance tries to save a tiddler with whitespace in the name and nothing else.

eg. store.saveTiddler(' ', ' ','hello world','boo', new Date(),[],config.defaultCustomFields); autoSaveChanges([store.getTiddler(" ")])

The tiddler gets added to the store and saved, however does not appear in the timeline. However it is part of the document.

It is a little confusing and nothing major, but I think it might be useful to disallow names with nothing other than whitespace.

[MartinBudden]

This is a case of a programming error on the part of the plugin writer - generally speaking the core does not protect against programming errors, it only protects against user errors.