Layer
Similar concept to DXF layers.  Layers contain Entities, have a default
      colour and linestyle and their visibility can be controlled.
Example1 C#: Create layers, set some properties, catch a pointer to existing layers, add drawing object to layers.
Public Fields
| Entities | 
          CamBam.CAD.EntityCollection The list of Entities in this layer.  | 
          |
| ModificationCount | 
          System.Int64 | 
Properties
| Alpha | 
          System.Single  | 
          |
| CADFile readonly  | 
          CADFile  | 
          |
| Color | 
          System.Drawing.Color  | 
          VB | 
| Name | 
          System.String  | 
          |
| Parent | 
          System.Object  | 
          |
| PenWidth | 
          System.Single  | 
          |
| Tag | 
          System.String  | 
          |
| Visible | 
          System.Boolean  | 
          |
| XmlColor | 
          System.String  | 
          
Methods
| ClearEventHandlers | 
          Void ClearEventHandlers () | |
| Clone | 
          Object Clone () | |
| PropertyChanged | 
          Void PropertyChanged (String propertyname, Object newvalue) | |
| PropertyChanging | 
          Void PropertyChanging (String propertyname, Object newvalue) | |
| ToString | 
          String ToString () | |
| Update | 
          Void Update () Instructs the primitive to refresh any internal data if the the object has changed.  |