New code for adding todo, priority and tags

Altered items:
anaphora, require, org, simple-call-tree-major-mode-alist,
simple-call-tree-org-todo-state, simple-call-tree-org-todo-states,
simple-call-tree-org-priority-levels, simple-call-tree-mode,
simple-call-tree-tags-regexp, simple-call-tree-analyze,
simple-call-tree-get-function-at-point, simple-call-tree-get-tags,
simple-call-tree-set-attribute, simple-call-tree-set-todo,
simple-call-tree-set-priority, simple-call-tree-set-tags,
simple-call-tree-list-callees-recursively,
simple-call-tree-insert-item, simple-call-tree-insert-org-header,
simple-call-tree-jump-to-function
New macro: simple-call-tree-get-item

Also new commands & keybindings for changing TODO state.

Altered items:
simple-call-tree-org-todo-states,
simple-call-tree-org-priority-levels, simple-call-tree-get-item,
simple-call-tree-mode, simple-call-tree-invert,
simple-call-tree-set-attribute, simple-call-tree-set-todo,
simple-call-tree-next-todo, simple-call-tree-prev-todo,
simple-call-tree-set-priority, simple-call-tree-current-function,
simple-call-tree-list-callees-recursively,
simple-call-tree-narrow-to-function, simple-call-tree-apply-command