* helm.el (helm-flatten-list): Allow removing nulls.
Add sources for classes and generic fns in helm-apropos.

* helm-elisp.el (helm-apropos-function-list): New user var.
(helm-def-source--emacs-functions): Remove classes and gen fns.
(helm-def-source--eieio-generic,
helm-def-source--eieio-classes): news.