support showing Titles split by first letter or as flat list

Changed book.php and base.php to support showing "All Books"  split by
first letter, or as a flat list similar as can be configured for
authors. For this I added a setting in config_default.php
named 'cops_titles_split_first_letter'. It accepts the same values as
for authors, 1 to split by first letter, 0 to show as flat list.

affected classes:

base.php:class Entry
base.php:class PageAllBooks 

book.php:added query
book.php:class Book
book.php:added static function
book.php:public function getDatas changed to filter out ORIGINAL_EPUB in
book popups since it also isn't shown in the regular book list. 

Also included the changes to the English language file. Feel free to
ignore these.