Fixes #481 - Sort buffer views alphabetically.

Fixes #481 - Sort buffer views alphabetically.
Selecting sort alphabetically prohibits now reordering the buffer view.
If you edit an existing buffer view in the settings page checking
"sort alphabetically" will cause a resort. Unchecking doesn't
"randomize" (or whatever) the view and leaves it in the sorted state,
but you can now reorder it again.