* lisp/buff-menu.el (Buffer-menu-filter-predicate): New defvar-local.
(list-buffers-noselect): Add new optional arg 'filter-predicate'.
Set 'Buffer-menu-filter-predicate' to 'filter-predicate'.
(list-buffers--refresh): Use 'Buffer-menu-filter-predicate'.
* lisp/progmodes/project.el (project-prefix-map): Bind "\C-b" to
'project-list-buffers'.
(project-list-buffers): New command.