fix the comment to describe the real return values lot of work on the

* encoding.c: fix the comment to describe the real return values
* pattern.c xpath.c include/libxml/pattern.h: lot of work on
  the patterns, pluggin in the XPath default evaluation, but
  disabled right now because it's not yet good enough for XSLT.
  pattern.h streaming API are likely to be changed to handle
  relative and absolute paths in the same expression.
Daniel
diff --git a/encoding.c b/encoding.c
index da063e2..35c5443 100644
--- a/encoding.c
+++ b/encoding.c
@@ -223,7 +223,7 @@
  *
  * Take a block of ISO Latin 1 chars in and try to convert it to an UTF-8
  * block of chars out.
- * Returns 0 if success, or -1 otherwise
+ * Returns the number of bytes written if success, or -1 otherwise
  * The value of @inlen after return is the number of octets consumed
  *     if the return value is positive, else unpredictable.
  * The value of @outlen after return is the number of octets consumed.
@@ -311,7 +311,8 @@
  * Take a block of UTF-8 chars in and try to convert it to an ISO Latin 1
  * block of chars out.
  *
- * Returns 0 if success, -2 if the transcoding fails, or -1 otherwise
+ * Returns the number of bytes written if success, -2 if the transcoding fails,
+           or -1 otherwise
  * The value of @inlen after return is the number of octets consumed
  *     if the return value is positive, else unpredictable.
  * The value of @outlen after return is the number of octets consumed.