CAD: choose the AutoCAD version to write DWG and DXF in (#489) - #497

'Bitmap.Save(string, int?)' is obsolete: 'Use the overload accepting BitmapEncoderOptions instead.'

Nullable value type may be null.

Dereference of a possibly null reference.

Dereference of a possibly null reference.

Dereference of a possibly null reference.

Dereference of a possibly null reference.

Possible null reference argument for parameter 'collection' in 'void Assert.Contains<string>(string expected, IEnumerable<string> collection)'.

Ambiguous reference in cref attribute: 'DocumentReaders.DecodeText'. Assuming 'Filee.Engines.Hwp.Hwpx.DocumentReaders.DecodeText(byte[])', but could have also matched other overloads including 'Filee.Engines.Hwp.Hwpx.DocumentReaders.DecodeText(byte[], int)'.

'IPdfImage.Bounds' is obsolete: 'Use BoundingBox instead.'