(org-archive-subtree): Use end-of-subtree as insertion

(org-archive-subtree): Use end-of-subtree as insertion
	point and control the number of empty lines.
	(org-paste-subtree): Limit the number of empty lines at the end of
	the inserted tree.
	(org-agenda): Use buffer name of current file for narrowing.
	(org-export-as-xml): Command removed.
	(org-export-xml-type): Option removed.
	(org-mode-map): Call `org-export-as-xoxo' directly.
	(org-get-indentation): New optional argument LINE.
	(org-fix-indentation, org-remove-tabs): New functions.
	(org-export-as-ascii, org-ascii-level-start): Determine and apply
	correct indentation for headlines that are converted it items.
	(org-skip-comments): Remove table lines that contain narrowing
	cookies but no other non-empty fields.
	(org-set-tags): Allow groups of mutually exclusive tags.
	(org-cmp-time): Sort 24:21 before items without time.
	(org-get-time-of-day): Fixed the interpretation of 12pm and 12am.
	(org-open-at-point): Require double colon also for numbers.