Option/Nullable type for not required properties

[sergey-tihon]

Type provider should provide optional types for the not required properties.

Initially proposed by @yodiz here #91 (comment) , user votes are here https://twitter.com/sergey_tihon/status/933323948791607297

Option (default behavior)

{
  PetId : int
  PrimaryCatergory : PetCategory
  SecondayCategory : PetCategory option 
}

Nullable

Nullable should play nicely with F# as well, but primary rationale to support it is C# interop

{
  PetId : int
  PrimaryCatergory : PetCategory
  SecondayCategory : Nullable<PetCategory> 
}

[sergey-tihon]

This feature is implemented in v0.10.0-alpha2