Expand helper library

[bogdanpolak]

See article:
http://blogs.conceptfirst.com/2006/05/08/class-helpers-good-or-bad.html

TCanvasHelper =  class helper for TCanvas
  procedure FillGradient( Bounds: TRect; StartColour, EndColour: TColor; IsHorizontal: boolean );
end;

TListHelper = class helper for TList
  procedure FreeSelfAndContainedObjects;
end;

TDatasetHelper = class helper for TDataSet
public
  procedure InsertIntoStrings( Strings: TStrings; NameField: string; IndexField: string = '' );
  function HaveFieldsChanged: boolean;
  procedure PostIfEditing;
end;

TFieldHelper = class helper for TField
public
  function HasChanged: boolean;
end;

TTreeNodesHelper = class helper for TTreeNodes
public
  procedure ExpandToLevel( Level: integer );
  function FindOrCreateNode( NodePath: string ): TTreeNode;
end;
  
TRectHelper = record helper for TRect
  function ContainsPoint( Point: TPoint ): boolean;
end;

[bogdanpolak]

TPageControlHelper:
Add Tab with frame (look Ugly VCL Project)

https://github.com/bogdanpolak/ugly-vcl-project/blob/a6d46406ea2349f1e91ccf958514f9185b669662/project/Form.Main.pas#L377-L395