Updates to the Standard Steps

Here's what I've updated:

  * Added authentication support to p:http-request

  * Added encoding and charset options to p:unescape-markup to work
    better with p:http-request results that are encoded.

  * Added text describing how xsl:output is ignored in p:xslt as we
don't serialize

  * Added text describing how p:xslt must produce a well-formed document.

  * Added serialization options to p:store and p:http-request

  * Added pointer to XSLT 2.0 and XQuery 1.0 Serialization for interpretation
    of serialization options.

You'll find the update in the usual spot:

   http://www.w3.org/XML/XProc/docs/langspec.html

-- 
--Alex Milowski
"The excellence of grammar as a guide is proportional to the paucity of the
inflexions, i.e. to the degree of analysis effected by the language
considered."

Bertrand Russell in a footnote of Principles of Mathematics