Add Json Alias annotation

[SentryMan]

Adds a new annotation we can use to specify alternate deserialization names.

@Json
@Getter
@Setter
public class TestClass {

  @Json.JsonAlias({"something", "something2"})
  private String alias;

  private String s;

  private int i;

  private Integer integer;

  private char ch;

  private Character chara;

  private List<String> list;
}

generated adapter fromJson looks like.

  @Override
  public TestClass fromJson(JsonReader reader) {
    TestClass _$testClass = new TestClass();

    // read json
    reader.beginObject();
    reader.names(names);
    while (reader.hasNextField()) {
      String fieldName = reader.nextField();
      switch (fieldName) {
        case "something":
        case "something2":
        case "alias": {
          _$testClass.setAlias(stringJsonAdapter.fromJson(reader)); break;
        }
        case "s": {
          _$testClass.setS(stringJsonAdapter.fromJson(reader)); break;
        }
        case "i": {
          _$testClass.setI(pintJsonAdapter.fromJson(reader)); break;
        }
        case "integer": {
          _$testClass.setInteger(integerJsonAdapter.fromJson(reader)); break;
        }
 and so on...

[rbygrave]

I love it

[rbygrave]

whitespace

[rbygrave]

we should add a test that uses "something", "something2" and "alias"