Enhanced xmlXPathRunStreamEval, fixed handling of depth/level for cases

* xpath.c, pattern.c: Enhanced xmlXPathRunStreamEval, fixed
  handling of depth/level for cases like union operator
  (bug #306348 reported by Bob Stayton).  Also enhanced
  several comments throughout pattern.c.
* doc/apibuild.py: fixed problem in handling of
  'signed' declaration.  Rebuilt the docs.
diff --git a/doc/APIchunk5.html b/doc/APIchunk5.html
index 7a82a2c..f91da3d 100644
--- a/doc/APIchunk5.html
+++ b/doc/APIchunk5.html
@@ -229,6 +229,8 @@
 <a href="html/libxml-xmlregexp.html#xmlRegExecPushString">xmlRegExecPushString</a><br />
 <a href="html/libxml-xmlregexp.html#xmlRegExecPushString2">xmlRegExecPushString2</a><br />
 <a href="html/libxml-relaxng.html#xmlRelaxNGValidatePushElement">xmlRelaxNGValidatePushElement</a><br />
+<a href="html/libxml-pattern.html#xmlStreamPush">xmlStreamPush</a><br />
+<a href="html/libxml-pattern.html#xmlStreamPushAttr">xmlStreamPushAttr</a><br />
 <a href="html/libxml-valid.html#xmlValidatePushElement">xmlValidatePushElement</a><br />
 </dd><dt>Pushes</dt><dd><a href="html/libxml-parserInternals.html#inputPush">inputPush</a><br />
 <a href="html/libxml-parserInternals.html#namePush">namePush</a><br />