Re-implementation of the Thrift Python library

Rough goals:

• Binary & Compact encodings

• Define & Export protocols using JSON, Python, Thrift IDL and YAML

• More straightforward libraries (e.g. "thriftit.BinaryCodec()" instead of "thrift.protocol.TBinaryProtocol.TBinaryProtocolFactory()")

• Try to fit in with Python better. For example, prefer dump & load over write & read and prefer underscored names over camelcase.

• Cyclic structs (named an anti-feature on the Thrift Wiki):

     struct Cons { 
         1: binary head,
         2: Cons tail optional
     }
  

• Parameterized Structs / Containers

     struct Tree<A> {
         1: Tree<A> left optional,
         2: Tree<A> right optional,
         3: A val required
     }
  
     struct Code { 
         1: string file, 
         2: i32 line_num,
         3: Tree<Expr> expr
     }
  

• Pure Python .thrift Parser

• Support alternative encodings where possible (Avro, Protocol Buffers, XDR, YAML, JSON)

• Tornado plugins

Implemented so far:

• Define protocol spec in JSON/YAML/Python

• Binary codec

• Compact codec

• Cyclic structs

• Dynamically define structs in Python:

   class Enum(int):
      ...
  
   class MethodEnum(Enum):
      GET = 1
      POST = 2
      HEAD = 3
      DELETE = 4
  
   class HTTPRequest(thriftit.Struct):
       addr = thriftit.Field(thriftit.I64Type, 1, int, 0)
       method = thriftit.Field(thriftit.I8Type, 2, MethodEnum, MethodEnum.GET)
       uri = thriftit.Field(thriftit.ByteStringType, 3, str, '')
       body = thriftitit.Field(thriftit.ByteStringType, 4, str, '')