Add support for message reactions

[Terrance]

The latest Android beta introduced emoticon reactions on messages.

Messages now carry an emotions property, for example:

{"from": "https://db5-client-s.gateway.messenger.live.com/v1/users/ME/contacts/8:fred.2",
 "type": "Message",
 "content": "Hello.",
 "conversationLink": "https://db5-client-s.gateway.messenger.live.com/v1/users/ME/conversations/8:joe.4",
 "clientmessageid": "12345678901234567890",
 "composetime": "2017-01-01T00:00:00.000Z",
 "version": "1483228800000",
 "messagetype": "RichText",
 "originalarrivaltime": "2017-01-01T00:00:00.000Z",
 "id": "1483228800000",
 "properties": {"emotions": [{"key": "sarcastic",
                              "users": [{"mri": "8:joe.4",
                                         "time": 1483228800000}]}]}}

These are not currently visible in Skype for Web, though the data is available over the long poll API.

[mihalt]

Hi! How is it going? As I see, there is not emotions on Skype Event Loop yet.