Allow to use custom tsconfig or custom compilerOptions

[zzarcon]

Questions:

• Should this options override the default one or merge it?
• Should we use something like ts-react-toolbox.config?
• Should it just be command args? $ yarn ts-react-toolbox build -o '{...}'?

[theKashey]

personally I have no case when I needed a project specific config.

[zzarcon]

I had one yesterday in where I was converting some .js files into .ts, and the noImplicitAny was causing a crazy amount of errors, which I didn't want to fix hehe

[theKashey]

Why not use ./tsconfig as a source of truth, and update it as a postinstall hook (and then I could just stash changes I don't want)?