Add manga straight into a category from catalogues (#737)

* Add feature mention in issue #625

app/src/main/res/values/strings.xml

@@ -134,6 +134,8 @@
     <string name="pref_start_screen">Start screen</string>
     <string name="pref_language">Language</string>
     <string name="system_default">System default</string>
+    <string name="default_category">Default category</string>
+    <string name="default_category_summary">Always ask</string>
 
       <!-- Reader section -->
     <string name="pref_fullscreen">Fullscreen</string>
@@ -269,6 +271,7 @@
     <string name="no_valid_sources">Please enable at least one valid source</string>
     <string name="no_more_results">No more results</string>
     <string name="local_source">Local manga</string>
+    <string name="invalid_combination">Default can\'t be selected with other categories</string>
 
     <!-- Manga activity -->
     <string name="manga_not_in_db">This manga was removed from the database!</string>