Codegen dataclassess (facebookexperimental#79)

* Wrote test to validate primitive type mapping

* Added test for type alias definition

* Built dataclasses code generator

* Built test for dataclassess code generator

* Changed to unittest

* Updated struct dataclass function to support all types

* feat: built dataclass generator

* Added copyright

* Added nested struct support

* Added test for nested struct

* Feat: update functions and put it in a class.

* chore: update tests

* Casted types to pass pyre check

* Updated types

* chore: Refactor typing.cast code

* Added copyright

* refactor: update tests to reflect new schema changes

* fix: Fix pyre typing errors

[jdwp] do not emit array length and union tag fields

[jdwp] map union tags and array lengths to int

[jdwp] fix type for union fields

[jdwp] fix names of fields containing spaces

[jdwp] generate projects.jdwp.runtime.structs

[jdwp] add tests importing components of the runtime library

implement async abstract methods, add TCP conn

update files

update conn and streams

add buck deps

add jvm connection and implement jvm streams

add a base class for jdwp structs

[jdwp] generate projects.jdwp.runtime.structs

[jdwp] add tests importing components of the runtime library

fix fail build

[jdwp] fix type checker fails