* TextBoxBase.cs: Default selection length is -1, need to do

    * TextBoxBase.cs: Default selection length is -1, need to do
        * some
        more testing on windows to see when this is used for the
property.
        - Redid the Lines [] property to that we properly remove soft
          line
        breaks
        - added support for preserving carriage returns
        -  CanUndo is not a variable like 'is undo enabled' it just
           returns
        true if there is undo operations available.
        - AppendText doesn't need to grab the last tag itself anymore,
        this happens automatically when we move the cursor.
        * TextControl.cs: Add CompoundActions to the undo class. This
        allows combining the other operations into one big option.  ie a
        paste will combine { delete old, insert new, move cursor }
        - Add InsertString undo operation
        - New method for deleting multiline text
        - Add carriage returns to lines. So we can preserve carriage
        returns when text is 'roundtripped'

svn path=/trunk/mcs/; revision=68995