[TASK] Add balance_change array to transaction response, computed from metadata

> No it isn't.
> What is "the standard?"

All of Google's top recommended style guides are in agreement, except GitHub's, which eschews all semicolons. None of the ones I saw recommend what we are currently doing, not even the AirBnb style guide that we forked.

JSLint and JSHint derive from Douglas Crockford's style recommendations:
http://javascript.crockford.com/code.html

Google's style guide (explicitly clarifies the case we are discussing):
https://google-styleguide.googlecode.com/svn/trunk/javascriptguide.xml#semicolons

jQuery style guide:
http://contribute.jquery.org/style-guide/js/#comments