Switch to webpack workflow

A set of changes to match Blip and Clamshell's front-end workflow with Webpack.

@cheddar Do you want to take a look and tell me what you think? Thanks!
Hrm, I just noticed that this is actually returning the negation of the test, so my test would actually end up being inverted.

Fwiw, it's often nicer to have boolean methods always be the affirmative case.  It's relatively easy to `!` the result of a boolean, but if there is code out there that said `! this.isDisabledForm()` and that happens to be in a larger boolean it just gets confusing.  Complex boolean expressions are one of the primary sources of bugs I've seen.  Especially when things start getting not'd.

While I know this isn't necessarily part of this PR and it's probably not worth it to try to fix it at this point, 'cause that will likely introduce bugs, for future reference we should always strive to have boolean methods be in the affirmative.

Also, not that it really matters ('cause the original author of the code really doesn't matter, we will all change our coding styles and I'm sure you can find examples of where I haven't even followed my own advice), but if you ever wonder about who did what, git is good about that:

https://github.com/tidepool-org/jellyfish/blame/master/client/main.js?blame=true#L142-L147