[Mono-list] XmlConvert and XmlConstructs

[Dwivedi , Ajay Kumar]

Hi all,
	I have just checked in an updated XmlConvert.cs and added a helper
class XmlConstructs.cs
The XmlConstructs class has is almost entirely based on XmlChar class from
Xerces-2. It has methods to check the validity of characters.
Hackers working on Reading/Parsing XML may like to use/extend this class to
their convenience.

Happy Hacking,
Ajay