Log Message:
libgsf: update to 1.14.53.

libgsf 1.14.53

Morten:
	* Compilation fixes for libxml 2.13
	* Fix ABR in gsf-vba-dump.
	* Teach gsf (the tool) to handle odf properties.
	* Fix integer overflows affecting memory allocation.  [#34]

ThomasK:
	* Add missing "DocumentStatus" ole2 property.  [#35]

Zander Brown:
	* Avoid some undefined C behaviour in overflow checks.
	(Part of merge request 16; blame Morten for problems with
	the hand edits.)