MultiLineString serialization

[tkalcec]

MultiLineString is serialized as empty.
This might fix it.

MultiLineString.vb

Public Overrides ReadOnly Property Coordinates()
Get
Try
If LineStrings.Count = 0 Then
Return New Double() {}
Else
Dim out(0)()() As Double
Parallel.For(0, LineStrings.Count, Sub(i)
out(i) = LineStrings(i).Coordinates
End Sub)

                Return out
            End If
        Catch ex As Exception
            Return New Double() {}
        End Try
    End Get

End Property