improved doc, fixed errors

@@ -55,7 +55,17 @@ instead of `@` (or any other character). For instance:
     tex("@@@+@@@", "x", char="+")  => @@@x@@@
     
 So, string `s` is not escaped for LaTeX special characters, only the
-`args` are.
+`args` are. Other predefined Python functions are:
+
+ * `pygmentize(path, include=True, inline=False)`: typesets the
+   content of file `path` that is expected to be Python code, and it
+   outputs a LaTeX file that is included in main source if
+   `include=True`, either inline or displayed depending on `inline`
+   argument. If Pygments is not installed, the source code is used
+   verbatim.
+ * `escape(text)`: returns a copy if string `text` in which every
+   LaTeX special character has been properly escaped.x
+ * 
 
 Two more LaTeX commands are available: