Fix up minification

Right now, we use a slightly brokeass minification system. Here's what happened:

1. Originally, we had minification built into our Rollup pipeline. This is the best way to do the minification because it gets the map files right and because it can (at least in theory) be a bit smarter about the minification.
2. But it broke and caused all sorts of horribleness, as you can see in #357. I don't know what happened, but probably some part of the toolchain got upgraded and doesn't fit together right anymore
3. I switched the build to just run uglify on the output of the relevant transpile steps
4. You can switch between the old, better, broken method and the new, hacky, broken method by switching the TRUST_MINIFY const in build.js
5. Presumably the fix is either finding the right version of the toolchain deps or fiddling with some config.