New default value nil for `org-agenda-dim-blocked-tasks'
* org-agenda.el (org-agenda-dim-blocked-tasks): Default to
nil.
(org-agenda-dim-blocked-tasks): Make interactive and allow an
optional parameter 'invisible to hide blocked tasks instead of
just dimming them.
(org-agenda-mode-map): Bind `org-agenda-dim-blocked-tasks' to
"#".
With a default value of t for `org-agenda-dim-blocked-tasks',
any non-nil value for `org-enforce-todo-checkbox-dependencies' or
`org-enforce-todo-dependencies' (or both) will slow down the
agenda generation too much, which might surprise the user.