[Lambda] Add Lambda support for Skygear Data Type

[carmenlau]

• Add $type=record support in serializers/deserializers.
• Serialize lambda array arguments / dictionary arguments into Skygear data
  types using standard serializers.
• Deserialize return value from server using standard deserializers.

[carmenlau]

In commit 6db39e5, we get the "result" value
from a map is not always true. I found that the result in onSuccess will have key "result" only when the lambda response is array (See onResponse implementation below).

skygear-SDK-Android/skygear/src/main/java/io/skygear/skygear/Request.java

Line 106 in d211958

public void onResponse(JSONObject response) {

So in TypedLambdaResponseHandler, result.opt("result") doesn't work when the response is not array. It is not problem of TypedLambdaResponseHandler, it is problem of original lambda response implementation. If response is array, it will return JSONObject with result key. If response is dictionary, result key will be omitted. Since the underlying ResponseHandler onSuccess only accept JSONObject. Should we add onSuccess with JSONArray for the lambda case? We can discuss