Fix for default function namespace

All,

There was a contradiction: we said under "4 The XForms Function Library"
that "The XPath static context's default function namespace must be set to
this URI" (`http://www.w3.org/2002/xforms-functions`) but above in "3.1.1
Initializing the Static Context" we said to use the
default function namespace from XPath 2. Fixed with:


https://www.w3.org/community/xformsusers/wiki/index.php?title=XPath_Expressions_Module&diff=1373&oldid=1308

-Erik