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/de/LC_MESSAGES/core.po

@@ -9,99 +9,99 @@ msgstr ""
 "Language: de\n"
 "Plural-Forms: nplurals=2; plural=(n != 1);\n"
 
-#: core/app.py:37
+#: core/app.py:40
 msgid "There are no marked duplicates. Nothing has been done."
 msgstr ""
 
-#: core/app.py:38
+#: core/app.py:41
 msgid "There are no selected duplicates. Nothing has been done."
 msgstr ""
 
-#: core/app.py:39
+#: core/app.py:42
 msgid ""
 "You're about to open many files at once. Depending on what those files are "
 "opened with, doing so can create quite a mess. Continue?"
 msgstr ""
 
-#: core/app.py:98
+#: core/app.py:110
 msgid "will only be able to delete, move or copy 10 duplicates at once"
 msgstr ""
 
-#: core/app.py:232
+#: core/app.py:254
 msgid "No duplicates found."
 msgstr "Keine Duplikate gefunden."
 
-#: core/app.py:245
+#: core/app.py:267
 msgid "All marked files were copied successfully."
 msgstr ""
 
-#: core/app.py:246
+#: core/app.py:268
 msgid "All marked files were moved successfully."
 msgstr ""
 
-#: core/app.py:247
+#: core/app.py:269
 msgid "All marked files were successfully sent to Trash."
 msgstr ""
 
-#: core/app.py:274
+#: core/app.py:296
 msgid ""
 "You cannot delete, move or copy more than 10 duplicates at once in demo "
 "mode."
 msgstr ""
 
-#: core/app.py:285
+#: core/app.py:307
 msgid "'{}' already is in the list."
 msgstr ""
 
-#: core/app.py:287
+#: core/app.py:309
 msgid "'{}' does not exist."
 msgstr ""
 
-#: core/app.py:294
+#: core/app.py:316
 msgid ""
 "All selected %d matches are going to be ignored in all subsequent scans. "
 "Continue?"
 msgstr "%d Dateien werden in zukünftigen Scans ignoriert werden. Fortfahren?"
 
-#: core/app.py:354
+#: core/app.py:376
 msgid "copy"
 msgstr "kopieren"
 
-#: core/app.py:354
+#: core/app.py:376
 msgid "move"
 msgstr "verschieben"
 
-#: core/app.py:355
+#: core/app.py:377
 msgid "Select a directory to {} marked files to"
 msgstr "Wählen sie einen Ordner zum {} der ausgewählten Dateien"
 
-#: core/app.py:381
+#: core/app.py:403
 msgid "Select a destination for your exported CSV"
 msgstr ""
 
-#: core/app.py:406
+#: core/app.py:428
 msgid "You have no custom command set up. Set it up in your preferences."
 msgstr ""
 "Sie haben keinen eigenen Befehl erstellt. Bitte in den Einstellungen "
 "konfigurieren."
 
-#: core/app.py:512 core/app.py:523
+#: core/app.py:535 core/app.py:546
 msgid "You are about to remove %d files from results. Continue?"
 msgstr "%d Dateien werden aus der Ergebnisliste entfernt. Fortfahren?"
 
-#: core/app.py:543
+#: core/app.py:566
 msgid "{} duplicate groups were changed by the re-prioritization."
 msgstr ""
 
-#: core/app.py:563
+#: core/app.py:586
 msgid "Collecting files to scan"
 msgstr "Sammle Dateien zum Scannen"
 
-#: core/app.py:574
+#: core/app.py:597
 msgid "The selected directories contain no scannable file."
 msgstr "Der ausgewählte Ordner enthält keine scannbare Dateien."
 
-#: core/app.py:613
+#: core/app.py:636
 msgid "%s (%d discarded)"
 msgstr "%s (%d verworfen)"
 
@@ -208,3 +208,35 @@ msgstr "%d/%d verifizierte Paare"
 #: core_pe/matchexif.py:18
 msgid "Read EXIF of %d/%d pictures"
 msgstr ""
+
+#: core/app.py:58
+msgid "Scanning for duplicates"
+msgstr "Suche nach Duplikaten"
+
+#: core/app.py:59
+msgid "Loading"
+msgstr "Laden"
+
+#: core/app.py:60
+msgid "Moving"
+msgstr "Verschieben"
+
+#: core/app.py:61
+msgid "Copying"
+msgstr "Kopieren"
+
+#: core/app.py:62
+msgid "Sending to Trash"
+msgstr "Verschiebe in den Mülleimer"
+
+#: core/app.py:65
+msgid "Sending files to the recycle bin"
+msgstr "Sende Dateien in den Mülleimer"
+
+#: core/app.py:246
+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 ""
+"Eine vorherige Aktion ist noch in der Bearbeitung. Sie können noch keine "
+"Neue starten. Warten Sie einige Sekunden und versuchen es erneut."