Received balance incorrectly includes tx change

[STRML]

If change from a tx is sent back to the same address, it is erroneously counted in the totalReceived.

There is an issue on insight-api for this, but the bug lies here:

bitpay/insight-api#351

Consider the massive discrepancy in total received as shown in that ticket between Insight and all other explorers.

[braydonf]

I think we're going to need some additional indexes to make querying the satoshis being spent for each input faster here (see #376 (comment)). There could also be some benefits with caching results, so we may want to take a look at adding that, and calculating the change in that case should be simple. However, there may be pros and cons to consider there that we should be careful.

[braydonf]

Here is another case where we may need to lookup the previous transaction for each input to create the indexes: #397

[STRML]

Looks good in 3.0. Appears we can finally do this right this time. We're going to upgrade our Testnet instances and see how it goes.