Add a new wrapping mode to the TextEditor that will wrap lines at the
spaces between words.
Replace the previous menubar checkbox 'Wrapping Mode' in HackStudio and
the TextEditor with an exclusive submenu which allows switching between
'No wrapping', 'Wrap anywhere' and 'Wrap at words'. 'Wrap anywhere' (the
new 'Wrap lines') is still the default mode.
Setting the wrapping mode in the constructors of the TextEditorWidget
and HackStudio has been removed, it is now set when constructing the
menubar actions.
