[PATCH] Re-localise conflict prompt

The conflict prompt is no longer localised, probably because of an
oversight. Only the "long" descriptions are marked for translation but
there is no actual corresponding gettext call; the "short"
descriptions not at all. This patch attempts to rectify that.

I'm not altogether happy with the localisation of short single-word
strings such as "merge" and "edit" since they may need to be
translated differently depending on where they occur. I couldn't find
any use of contexts in the localisation of Subversion and don't know
if starting using them would cause portability problems.

Another point of interest is whether to translate the conflict option
codes ("mc", "df", etc). They weren't before, and this patch does not
change that, but I believe they should be --- they are mnemonic in
English only. We do localise short answers to yes/no questions
("y"/"n"). I would be interested in hearing what the other translators
think about this.

[[[
Make the conflict prompt correctly localised again (except the
option codes, which never were).

* subversion/svn/conflict-callbacks.c
   (resolver_option_t,
   text_conflict_options, prop_conflict_options, obstructed_add_options,
   tree_conflict_options, tree_conflict_options_update_moved_away,
   tree_conflict_options_update_deleted,
   tree_conflict_options_update_replaced): Localise short_desc.
   (prompt_string): Localise the static part of the prompt, call gettext
    for translated strings, and measure the width of the generated
prompt
    correctly for UTF-8.
]]]