Subspace 1.2.1

Using babel instead of webpack to make Subspace tree-shakeable

Generally for a library, webpack is not used to produce the build in dist/. rather, but babel and let downstream projects make the choice of webpack or rollup, etc. Subspace's node and browser builds were heavy and there was no hope a downstream developer's build tools can treeshake.

This minor release uses babel to build the sources into dist/ for nodejs, lib/ for the browser and module/ for es6. A DApp (or project, generally speaking) that makes use of Subspace will, with its own front-end tooling (e.g. webpack or rollup, in the context of create-react-app for example) be responsible for tree shaking and creating builds.

In addition to this change, dependency versions were bumped up.