Enhancement of list sort

[GoogleCodeExporter]

I have a PRS-650, using last version of prs+ firmware.

Navigating throw my books, default sorting is "by Added order". You can change 
it using option in top right corner. But this change is not saved, so when you 
quit the current screen sorting come back to "by Added order".

Is it possible to add in preference an option to change the default way to sort 
list of books ?

Personally I have a lot of book collection with about 10 books per collection, 
and I don't add book one by one using Calibre. So sort list "by Added order" is 
awful for me, I've always to change to "by File Name" to get a correct sort (ie 
reading order)

More over I use "Next books in the Collection" (in prs+ preference > Manage 
books > Manage book list on welcome screen > Book selection) and as default 
order is "by Added Order" I don't see the "real" next book to read (for example 
I'm reading T2 and T4, T8, T5 are proposed on welcome screen not the T3, T4 and 
T5 as it should be). 

So if the team could work on this point it should be great !
Thanks a lot.

Original issue reported on code.google.com by alexbesn...@free.fr on 21 May 2013 at 5:36