Fixed typos and erros in REST xsd schemas

I tried to use xsd schemas to validate xml responses from eZ. But had some fails. For example "Warning: XMLReader::setSchema(): Element '{http:\/\/www.w3.org\/2001\/XMLSchema}complexType': The type has an 'all' model group in its {content type} and thus cannot be derived from a non-empty type, since this would produce a 'sequence' model group containing the 'all' model group; 'all' model groups are not allowed to appear inside other model groups."

* Fixed typos in xsd schemas
* Updated examples
* Fixed links between xsd schemas

should not be part of this PR