#9 Added Column.Name and allow to access column by its name

[Norbert Wagner]

This patch adds a Name property to the Column class that behaves just like Control's Name property.
Its value it set to the "(Name)" value as specified in the Designer.

The patch provides the basis to implement runtime column reordering later. (I will provide another patch in case this one gets accepted)

Patch Changes in detail:

- Adds a property "Name" to the Column class
- Adds ColumnCodeDomSerializer class that assigns Column's variable name to the Column.Name property (just like it is done for Control-based components)
- Sets the value of Column.Name to the specified text value when the column is created via one of the non-default constructors
(this is kind of a hack to improve backward compability. Probably new column-constructors would be better?)
- Makes ColumnCollection.IndexOf( string name ) look at Column.Name instead of Column.Text
- Adds a new ColumnCollection.IndexOfText( string text ) to provide old "search by text" functionality

Best Regards,
Norbert

[Norbert Wagner]