missing else in xlink.c

Obviously forgotten
python: fix drv_libxml2.py for python3 compatibility

https://bugzilla.gnome.org/show_bug.cgi?id=703979
Catch malloc error and exit accordingly

As pointed privately by Bill Parker <wp02855@gmail.com>
Another round of fixes for older versions of Python
Fix handling of mmap errors

https://bugzilla.gnome.org/show_bug.cgi?id=702320

as raised by Gaurav <ya1gaurav@gmail.com>
Two smal namespace tweaks

An improvement of the documentation, and an extra safety check
for xmlSetNs()
Remove occasional leading space in XPath number formatting

https://bugzilla.gnome.org/show_bug.cgi?id=704528

Somehow snprintf "%*.*e" can generate a leading space, remove it
Fix a wrong test

https://bugzilla.gnome.org/show_bug.cgi?id=704530

Arg is an array on the stack and can't be NULL
Avoid crash if allocation fails

https://bugzilla.gnome.org/show_bug.cgi?id=704527
xmlSchemaNewValue() may fail on OOM error