More friendly to TimeZones

[erayhanoglu]

Added TimeZone firendly abilities.

The new TDateTimeTZ record is used to store datetime values. TDateTimeTZ stores both original time and offset values. It has some helper function to convert original time to UTCTime, LocalTime or any other offset.

TDateTimeTZ values can be accesed from objects and arrays. Etc. Obj.Z['field'] returns a TDateTimeTZ value.

A new configuration record "JsonDeserializationConfig" has been added. It has UseLocalTime property to control how stored TDateTimeTZ values will be cast to TDateTime valus. When UseLocalTime is True (default) TDateTimeTZ values will be cast as LocalTime. Otherwise OrgTime will be used.