Mostly Fixes#893
A couple methods cache callbacks, and will require a larger refactor to fully denodeify.
Specifically, our methods involving web3 requests to sign a tx, sign a message, and approve or cancel either of those.
I think we should postpone those until the TxManager refactor, since it will likely handle this response caching itself.
Added new Qunit build process that will browserify the contents of `test/integration/lib` into the QUnit browser, allowing much more modular testing, including unit testing of our modules in our target browsers.
Made a basic unit test file of this form for the new encryptor module, which fails miserably because I've only just begun to work with it.
I've started with this blog post as a starting point, and will be adjusting it to our needs from there:
http://qnimate.com/passphrase-based-encryption-using-web-cryptography-api/
