finally converted the encoding module to the common error reporting

* encoding.c error.c include/libxml/xmlerror.h: finally converted
  the encoding module to the common error reporting mechanism
* doc/* doc/html/libxml-xmlerror.html: rebuilt
Daniel
diff --git a/doc/APIsymbols.html b/doc/APIsymbols.html
index 2091591..820b6f0 100644
--- a/doc/APIsymbols.html
+++ b/doc/APIsymbols.html
@@ -420,6 +420,7 @@
 <a href="html/libxml-xmlerror.html#XML_FROM_FTP">XML_FROM_FTP</a><br />
 <a href="html/libxml-xmlerror.html#XML_FROM_HTML">XML_FROM_HTML</a><br />
 <a href="html/libxml-xmlerror.html#XML_FROM_HTTP">XML_FROM_HTTP</a><br />
+<a href="html/libxml-xmlerror.html#XML_FROM_I18N">XML_FROM_I18N</a><br />
 <a href="html/libxml-xmlerror.html#XML_FROM_IO">XML_FROM_IO</a><br />
 <a href="html/libxml-xmlerror.html#XML_FROM_MEMORY">XML_FROM_MEMORY</a><br />
 <a href="html/libxml-xmlerror.html#XML_FROM_MODULE">XML_FROM_MODULE</a><br />
@@ -451,6 +452,11 @@
 <a href="html/libxml-xmlerror.html#XML_HTTP_UNKNOWN_HOST">XML_HTTP_UNKNOWN_HOST</a><br />
 <a href="html/libxml-xmlerror.html#XML_HTTP_URL_SYNTAX">XML_HTTP_URL_SYNTAX</a><br />
 <a href="html/libxml-xmlerror.html#XML_HTTP_USE_IP">XML_HTTP_USE_IP</a><br />
+<a href="html/libxml-xmlerror.html#XML_I18N_CONV_FAILED">XML_I18N_CONV_FAILED</a><br />
+<a href="html/libxml-xmlerror.html#XML_I18N_EXCESS_HANDLER">XML_I18N_EXCESS_HANDLER</a><br />
+<a href="html/libxml-xmlerror.html#XML_I18N_NO_HANDLER">XML_I18N_NO_HANDLER</a><br />
+<a href="html/libxml-xmlerror.html#XML_I18N_NO_NAME">XML_I18N_NO_NAME</a><br />
+<a href="html/libxml-xmlerror.html#XML_I18N_NO_OUTPUT">XML_I18N_NO_OUTPUT</a><br />
 <a href="html/libxml-entities.html#XML_INTERNAL_GENERAL_ENTITY">XML_INTERNAL_GENERAL_ENTITY</a><br />
 <a href="html/libxml-entities.html#XML_INTERNAL_PARAMETER_ENTITY">XML_INTERNAL_PARAMETER_ENTITY</a><br />
 <a href="html/libxml-entities.html#XML_INTERNAL_PREDEFINED_ENTITY">XML_INTERNAL_PREDEFINED_ENTITY</a><br />