Using default sizePolicy of ctkFittedTextBrowser

After setting the default value for ctkFittedTextBrowser,
we no longer need to force the sizePolicy value
See parent #304
Merge branch 'set-ctkFittedTextBrowser-default-policy'

* set-ctkFittedTextBrowser-default-policy:
  Using default sizePolicy of ctkFittedTextBrowser