Update todo example. fixes 'Create' that shouldn't happen

Currently, an `onBlur` creates a new todo on `TodoTextInput`. This makes sense for existing items but not for new items. I.e consider the following: 

1. cursor on new item ("What needs to be done?")
2. click 'x' on the first item. 

This results in two actions being fired: 

1. TODO_CREATE, with an empty string as 'text'
2. TODO_DESTROY

The proposed fix doesn't send a TODO_CREATE if `text.trim() === "")`
Merge pull request #1622 from gebrits/patch-1

Update todo example. fixes 'Create' that shouldn't happen