Updated Danish translation
Updated Danish translation of properties
textbuffer: fix selection replacement when pasting

It is more logical to first delete the selection and then pasting the
text. When the selection and the text contain tags, the new behavior is
more natural.

A segfault in paste_from_buffer() is also avoided. The segfault occurs when
the text to paste is deleted because it is the selection.

https://bugzilla.gnome.org/show_bug.cgi?id=339539
textbuffer: add unit tests for the clipboard

It tests gtk_text_buffer_paste_clipboard(),
gtk_text_buffer_copy_clipboard() and gtk_text_buffer_cut_clipboard() in
various situations, including when GtkTextTags are applied to the
selection.

The last test didn't pass.

https://bugzilla.gnome.org/show_bug.cgi?id=339539
Improve doc of gtk_text_buffer_paste_clipboard()

It didn't explain the behavior when there is a non-empty buffer
selection.

https://bugzilla.gnome.org/show_bug.cgi?id=339539