fixed a typo pointed by Jeroen Ruigrok increased the APIs for xmlReader

* doc/xmllint.1 doc/xmllint.html doc/xmllint.xml: fixed a typo
  pointed by Jeroen Ruigrok
* include/libxml/xmlreader.h include/libxml/xmlschemas.h: increased
  the APIs for xmlReader schemas validation support
* xmllint.c xmlreader.c xmlschemas.c: xmlReader schemas validation
  implementation and testing as xmllint --stream --schema ...
Daniel
diff --git a/doc/xmllint.1 b/doc/xmllint.1
index 3875961..0a49b85 100644
--- a/doc/xmllint.1
+++ b/doc/xmllint.1
@@ -144,7 +144,7 @@
 
 .TP
 \fB\-\-xmlout\fR
-Used in conjusntion with \fB\-\-html\fR\&. Usually when HTML is parsed the document is saved with the HTML serializer, but with this option the resulting document is saved with the XML serializer\&. This is primarily used to generate XHTML from HTML input\&.
+Used in conjunction with \fB\-\-html\fR\&. Usually when HTML is parsed the document is saved with the HTML serializer, but with this option the resulting document is saved with the XML serializer\&. This is primarily used to generate XHTML from HTML input\&.
 
 .TP
 \fB\-\-push\fR