[FileObject] Add required attribute Directory (34) to FileObject implementation

[Broekman]

[FileObject] Add required attribute Directory (34) to FileObject implementation

Refer to CIP Vol1 (3.24) - 5A-42.2

Class code: 0x37
Attribute ID: 32
Instance ID: 0 (base class)
Access rule: Get
Name: Directory
Data type: Array of: Struct of:

• Instance number (UINT)
• Instance name (STRINGI)
• File name (STRINGI)

Also requires implementation of STRINGI:

• Number (USINT)
• Array of: struct of: Strings
  • LanguageChar1 (USINT
  • LanguageChar2 (USINT)
  • LanguageChar3 (USINT)
  • CharStringStruct (USINT) - 0XD0 STRING, 0xD5 STRING2, 0xD9 STRINGN, 0xDA SHORT_STRING
  • CharSet (UINT)
  • InternationalString (array of 8-bit octets - datatype as defined in CharStringStruct)

Already have this working but in a quick and dirty way. Will work it neatly into the library later. At least will add the structure but if wanted I could also add e.g. a functionality to retrieve a list of files from a device.