Fix bugs wrt invisibility handline.

Fix bugs wrt invisibility handline.

* org-compat.el (org-move-to-column): Always ignore invisible
text in agenda buffer, and when there is both a bracket link
and '(org-link) as a member of `buffer-invisibility-spec'.
Add a docstring.

* org.el (org-align-tags-here): Add docstring and remove
useless arguments when calling `org-move-to-column'.

* org-table.el (org-table-copy-down)
(org-table-find-dataline, org-table-move-row)
(org-table-insert-hline, org-table-kill-row):
* org-agenda.el (org-agenda-next-item)
(org-agenda-previous-item, org-agenda-todo)
(org-agenda-priority, org-agenda-show-new-time)
(org-agenda-clock-in, org-agenda-clock-out): Remove useless
arguments when calling `org-move-to-column'.

This fixes the issue about S-RET not placing the cursor in the right
table field when M-x org-toggle-link-display RET removed '(org-link)
from `buffer-invisibility-spec' and some other discrepancies (like
S-M-<up> not restoring point correctly when there is a bracket link
before point, or M-x org-clock-display RET not aligning overlays
correctly, etc.

Thanks to Matt Lundin and Michael Brand for tracking issues
about this.