adding a new set of API for parsing xmlReadDoc() xmlReadFile() ...

* parser.c include/libxml/parser.h: adding a new set of
  API for parsing xmlReadDoc() xmlReadFile() ... xmlReadIO()
  and xmlCtxtReadDoc() ... xmlCtxtReadIO(). That with
  a clear define of xmlParserOption, xmlCtxtUseOptions()
  should simplify custom parsing without being tempted to
  use global variables, and xmlCtxtReset() should allow reuse
  of a context for multiple parsing.
* xmllint.c: switched to use xmlReadXXX, allow options to
  be used simultaneously with less troubles.
* tree.c: simple warning removal
* doc/apibuild.py: small fix
* doc/libxml2-api.xml win32/libxml2.def.src: updated
Daniel

python/libxml2class.txt

@@ -110,6 +110,10 @@ parseEntity()
 parseFile()
 parseMemory()
 pedanticParserDefault()
+readDoc()
+readFd()
+readFile()
+readMemory()
 recoverDoc()
 recoverFile()
 recoverMemory()
@@ -655,6 +659,7 @@ Class xmlTextReader(xmlTextReaderCore)
     ConstName()
     ConstNamespaceUri()
     ConstPrefix()
+    ConstString()
     ConstXmlLang()
     CurrentDoc()
     CurrentNode()
@@ -815,6 +820,12 @@ Class parserCtxt(parserCtxtCore)
 
     # functions from module parser
     clearParserCtxt()
+    ctxtReadDoc()
+    ctxtReadFd()
+    ctxtReadFile()
+    ctxtReadMemory()
+    ctxtReset()
+    ctxtUseOptions()
     initParserCtxt()
     parseChunk()
     parseDocument()