WIP - initial commit

If the message has two newlines it will create many data events. For example this is the event received by the SSE proxy:
```erlang
<<"data: {\"tigertext_api\":{\"version\":\"1.0\",\"timestamp\":\"2014-7-24T4:22:47Z\",\"app\":\"http_sse\",\"app_version\":\"1.0\",\"event_id\":\"34c62d1b-e5ff-469e-a0f0-a0f28b7f7ea3\",\"event\":{\"tigertext:iq:update\":{\"xmlns\":\"tigertext:iq:update\",\"entities\":[{\"xmlns\":\"tigertext:entity:group\",\"token\":\"ilZDRlqUQqK_1t8-GCoGdQ\",\"name\":[],\"members\":[\"test\",\"test\"]}]}}}}\n\n">>
```

This is the answer sent to curl client:
```bash
data: data: {"tigertext_api":{"version":"1.0","timestamp":"2014-7-24T4:22:47Z","app":"http_sse","app_version":"1.0","event_id":"34c62d1b-e5ff-469e-a0f0-a0f28b7f7ea3","event":{"tigertext:iq:update":{"xmlns":"tigertext:iq:update","entities":[{"xmlns":"tigertext:entity:group","token":"ilZDRlqUQqK_1t8-GCoGdQ","name":[],"members":["test","test"]}]}}}}
data:
data:
```

This line https://github.com/inaka/lasse/blob/master/src/lasse_handler.erl#L202 is the responsible:
```erlang
build_data(Data) ->
    [[<<"data: ">>, X, <<"\n">>] || X <- binary:split(Data, <<"\n">>, [global])].
```

Mental note: discuss how to solve this issue with @jfacorro and @elbrujohalcon tomorrow morning.