Enable the user to supply a function from which imenu-anywhere will derive
the list of buffers to search.
Can be used to e.g. restrict the search to buffers which belong to the
current project.
Load cl-lib for 'mapcan' and 'delete-if'.
Merge pull request #10 from syohex/load-cl-lib

Load cl-lib for 'mapcan' and 'delete-if'.
Merge pull request #9 from eeeickythump/restrict-buffer-list

Enable user to restrict which buffers are searched.