* gui: Translate fancytree messages in Versions modal
Currently, the default fancytree info/error messages are used. This
means that a) they are English-only, and b) they are very generic. With
this commit, the messages are added to the translatable strings, and
they are also more specifically related to file versioning.
On a side note, the "moreData" string has been left out on purpose, as
it is not used in the current code. It can be added later if needed.
Signed-off-by: Tomasz Wilczyński <twilczynski@naver.com>