Bitstamp streaming: correct transaction ID

A new class, BitstampStreamingTransaction extends BitstampTransaction
BitstampStreamingTransaction

Extends BitstampTransaction, is built with @JsonProperty("id") instead of @JsonProperty("tid")
Create StreamTradesJSONTest

This is to test that the BitstampStreamingTransaction works as intended
Create example-stream-trades-data.json
Json trade parsed as BitstampStreamingTransaction
Cosmetic change
Test for Travis
Rename BitstampStreamingTransaction to BitstampStreamingTransaction.java
Delete test
Merge pull request #699 from stephane-coulomb/patch-3

Bitstamp streaming: correct transaction ID