Modernized progress window GUI

Following the refactoring that has been initiated in pdfmasher's
"vala" branch, I pushed more progress window logic into the
core.

The UI code is now a bit dumber than it used to be, and the core
now directly decides when the progress window is shown and
hidden. The "job finished" notification is also directly sent by the
core. Job description update logic is handled by a core gui
textfield.

Job description contsants also moved to the core, triggering
a localisation migration from "ui" to "core".

locale/fr/LC_MESSAGES/ui.po

@@ -12,26 +12,6 @@ msgstr ""
 "Language: fr\n"
 "Plural-Forms: nplurals=2; plural=(n > 1);\n"
 
-#: cocoa/inter/app.py:15 qt/base/app.py:38
-msgid "Scanning for duplicates"
-msgstr "Scan de doublons en cours"
-
-#: cocoa/inter/app.py:16 qt/base/app.py:39
-msgid "Loading"
-msgstr "Chargement en cours"
-
-#: cocoa/inter/app.py:17 qt/base/app.py:40
-msgid "Moving"
-msgstr "Déplacement en cours"
-
-#: cocoa/inter/app.py:18 qt/base/app.py:41
-msgid "Copying"
-msgstr "Copie en cours"
-
-#: cocoa/inter/app.py:19
-msgid "Sending to Trash"
-msgstr "Envoi vers corbeille"
-
 #: cocoa/inter/app_me.py:34
 msgid "Removing dead tracks from your iTunes Library"
 msgstr "Retrait des tracks mortes de votre librairie iTunes"
@@ -89,10 +69,6 @@ msgstr ""
 msgid "The iPhoto application couldn't be found."
 msgstr "iPhoto n'a pas pu être trouvée dans vos applications."
 
-#: qt/base/app.py:42
-msgid "Sending files to the recycle bin"
-msgstr "Envoi de fichiers à la corbeille"
-
 #: qt/base/app.py:95
 msgid "Quit"
 msgstr "Quitter"
@@ -126,14 +102,6 @@ msgstr "Vérifier les mises à jour"
 msgid "Open Debug Log"
 msgstr "Ouvrir logs de déboguage"
 
-#: qt/base/app.py:217 cocoa/base/en.lproj/Localizable.strings:0
-msgid ""
-"A previous action is still hanging in there. You can't start a new one yet. "
-"Wait a few seconds, then try again."
-msgstr ""
-"Une action précédente est encore en cours. Attendez quelques secondes avant "
-"d'en repartir une nouvelle."
-
 #: qt/base/app.py:257
 msgid "{} file (*.{})"
 msgstr "Fichier {} (*.{})"
@@ -872,9 +840,3 @@ msgstr "Réduire/agrandir"
 #: qt/base/deletion_options.py:46
 msgid " (unsupported)"
 msgstr ""
-
-#~ msgid " (Mac OS X or Linux only)"
-#~ msgstr " (Mac OS X ou Linux seulement)"
-
-#~ msgid "Re-Prioritize Results"
-#~ msgstr "Re-prioriser les résultats"