Improve transtable.{xml,xsl}, including:

- The structure of transtable.xml is revised.  <word> should be
   bracketed with <group>.

 - A sorting order of the FreeBSD mirror sites rendered using
   mirrors.xml has been determined by sort(1).

 - A template "transtable-lookup" has been added for localization on
   word-by-word basis.

 - Replace English month names in news.xml, press.xml, and
   advisories.xml with numbers that correspond to the names.
   The number->name translation is performed on the fly.

 - Since information in mirrors.xml is used in www/ tree, it depends on
   doc/ tree now.  When WITHOUT_DOC is defined it can be built without
   doc/ tree, but some information becomes unavailable.  For example,
   a list of the mirror sites generated in index.html becomes a dummy
   one, and calling "transtable-lookup" with a word returns the word
   itself.

Neither www/ nor doc/ build should be broken due to this commit, but
until the necessary changes are applied in the localized directories,
the transtable does not work; it simply generates non-localized contents
even if transtable.xsl is used.

share/sgml/transtable-local.xsl

@@ -12,5 +12,10 @@
   <!-- these params should be externally bound. The values
        here are not used actually -->
   <xsl:param name="transtable.xml" select="'./transtable.xml'" />
-  <xsl:param name="transtable-conv-element" select="''" />
+  <xsl:param name="transtable-sortkey.xml" select="'./transtable-sortkey.xml'" />
+
+  <xsl:param name="transtable-target-element" select="''" />
+  <xsl:param name="transtable-word-group" select="''" />
+  <xsl:param name="transtable-mode" select="''" />
+
 </xsl:stylesheet>