Compilation Mars.Utils function TryISO8601ToDate in XE7 and above

[Loucif-Fouad]

I'm trying to compile the group project of MARS.Enreprise in Delphi XE7 but and error accured in the MARS.Core.Utils.pas file at the function GuessTValueFromString where it calls TryISO8601ToDate that I think was introduced in earlier version of XE7.

[bogdanpolak]

@andrea-magni: It looks then TryISO8601ToDate was introduced in XE8 and ISO8601ToDate in XE7:

• http://docwiki.embarcadero.com/Libraries/XE6/en/System.DateUtils.ISO8601ToDate
• http://docwiki.embarcadero.com/Libraries/XE8/en/System.DateUtils.TryISO8601ToDate
  I think we need to refactor method GuessTValueFromString to use ISO8601ToDate and defined supported Delphi versions for MARS (in main README.md): XE7 - Rio. You can assign this to me. TryISO8601ToDate is used only once in MARS codebase and this looks like simple refactoring.

@JustMe2222222: Can you doble check that ISO8601ToDate is supported in XE7? Please try compile this code and give us feedback here:

uses
  System.DateUtils;

procedure TForm1.FormShow(Sender: TObject);
begin
  Caption := DateTimeToStr( ISO8601ToDate('2019-02-22T13:06:00.000+0100') );
end;