Rename a parameter to avoid gcc -Wshadow warning
Rename a parameter to avoid gcc -Wshadow warning

Compiling code including xmlwrapp/node.h with -Wshadow resulted in

warning: declaration of ‘text’ shadows a member of ‘xml::node::text’ [-Wshadow]

Fix this by simply renaming xml::node::text ctor argument to "content"
(used, rather than "contents", for consistency with the other similar
arguments).

vslavik/xmlwrapp,vadz/xmlwrapp,vslavik/xmlwrapp,vadz/xmlwrapp,vadz/xmlwrapp,vslavik/xmlwrapp