fixed missing dictionaries for Memory and Doc parser contexts (problem

* xmlschemas.c: fixed missing dictionaries for Memory and Doc
  parser contexts (problem reported on mailing list)
* doc/apibuild.py: small change to prevent duplicate lines
  on API functions list.  It will take effect the next time
  the docs are rebuilt.
diff --git a/xmlschemas.c b/xmlschemas.c
index d084f1e..303566e 100644
--- a/xmlschemas.c
+++ b/xmlschemas.c
@@ -3805,6 +3805,7 @@
     memset(ret, 0, sizeof(xmlSchemaParserCtxt));
     ret->buffer = buffer;
     ret->size = size;
+    ret->dict = xmlDictCreate();
     return (ret);
 }
 
@@ -3833,6 +3834,7 @@
     }
     memset(ret, 0, sizeof(xmlSchemaParserCtxt));
     ret->doc = doc;
+    ret->dict = xmlDictCreate();
 
     return (ret);
 }