configure.ac: Add test for allowing unaligned access. Add define to put in gstconfig.h.

configure.ac: Add test for allowing unaligned access.  Add define to put in gstconfig.h.

Original commit message from CVS:
* configure.ac: Add test for allowing unaligned access.  Add define
to put in gstconfig.h.
* docs/gst/gstreamer-sections.txt: New symbols
* docs/gst/tmpl/gstcompat.sgml: Check in changes made by gtkdoc
* docs/gst/tmpl/gstfilesrc.sgml:
* docs/gst/tmpl/gstparse.sgml:
* docs/gst/tmpl/gsttypes.sgml:
* docs/gst/tmpl/gstutils.sgml:
* docs/gst/tmpl/gstvalue.sgml:
* gst/gstconfig.h.in: Add GST_HAVE_UNALIGNED_ACCESS
* gst/gstutils.h: Add macros for unaligned memory access.  Useful
on most !i386/!powerpc architectures.  From Daniel Gazard
<daniel.gazard@free.fr>.  (bug #140156)
* po/af.po: Check in changes made by gettext.
* po/az.po:
* po/fr.po:
* po/nl.po:
* po/sr.po:
* po/sv.po: