Move compilation to use tsconfig.json files instead of hardcoded command lines

[dgoldstein0]

Currently there's one checked in tsconfig.json and it actually has different settings than what is used to compile it for testing - in that it says to use strictNullChecks which it doesn't actually compile under.

Part of my motivation for this is that I use a vim plugin which understands the tsconfig.json and tries to do some checking based on it, and it gets rather confused when the tsconfig is wrong - so this fixes that problem.

I do realize that these configs aren't ideal, but my thinking was to get the organization right, and then we can sort out bits like strictNullChecks, noImplicitAny, etc. which the code might not currently work with.

[dylans]

Seems reasonable, and becoming even more important with inheritance of tsconfig files making them far more useful going forward. Thanks!