Re-order visibility functions in "org.el"

Re-order visibility functions in "org.el"

* lisp/org-macs.el (org-outline-overlay-data):
(org-set-outline-overlay-data): Moved from "org.el".
* lisp/org.el (org-remove-empty-overlays-at):
(org-show-empty-lines-in-parent):
(org-files-list):
(org-entry-beginning-position):
(org-entry-end-position):
(org-subtree-end-visible-p):
(org-first-headline-recenter):
(org-flag-region):
(org-show-entry):
(org-show-children):
(org-show-subtree):
(org-hide-block-toggle-maybe):
(org-hide-block-toggle):
(org-hide-block-toggle-all):
(org-hide-block-all):
(org-cycle-hide-drawers):
(org-flag-drawer):
(org-previous-block):
(org-next-block): Move functions.