Option to mark newly added books

An option to mark newly added books with a temporary mark. Optionis in
Preferences->Adding books. Fixes #1238609 [[Enhancement] Set books as "Marked" when adding](https://bugs.launchpad.net/calibre/+bug/1238609)

src/calibre/db/view.py

@@ -13,7 +13,7 @@ from itertools import izip, imap
 from future_builtins import map
 
 from calibre.ebooks.metadata import title_sort
-from calibre.utils.config_base import tweaks
+from calibre.utils.config_base import tweaks, prefs
 from calibre.db.write import uniq
 
 def sanitize_sort_field_name(field_metadata, field):
@@ -426,4 +426,6 @@ class View(object):
         ids = tuple(ids)
         self._map = ids + self._map
         self._map_filtered = ids + self._map_filtered
+        if prefs['mark_new_books']:
+            self.toggle_marked_ids(ids)
 

src/calibre/gui2/preferences/adding.py

@@ -35,6 +35,7 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
                 (_('Create new record for each duplicate format'), 'new record')]
         r('automerge', gprefs, choices=choices)
         r('new_book_tags', prefs, setting=CommaSeparatedList)
+        r('mark_new_books', prefs)
         r('auto_add_path', gprefs, restart_required=True)
         r('auto_add_check_for_duplicates', gprefs)
         r('auto_add_auto_convert', gprefs)

src/calibre/gui2/preferences/adding.ui

@@ -151,6 +151,13 @@ Author matching is exact.</string>
          </property>
         </widget>
        </item>
+       <item row="3" column="2">
+        <widget class="QCheckBox" name="opt_mark_new_books">
+         <property name="text">
+          <string>&amp;Mark newly added books</string>
+         </property>
+        </widget>
+       </item>
       </layout>
      </widget>
      <widget class="QWidget" name="tab_4">

src/calibre/utils/config_base.py

@@ -400,6 +400,8 @@ def _prefs():
             help=_('Add new formats to existing book records'))
     c.add_opt('installation_uuid', default=None, help='Installation UUID')
     c.add_opt('new_book_tags', default=[], help=_('Tags to apply to books added to the library'))
+    c.add_opt('mark_new_books', default=False, help=_(
+        'Mark newly added books. The mark is a temporary mark that is automatically removed when calibre is restarted.'))
 
     # these are here instead of the gui preferences because calibredb and
     # calibre server can execute searches