Circular dependency warnings while building for browsers

[shreyasminocha]

src/electionguard/index.ts → dist/electionguard.js, dist/electionguard.umd.js...
(!) Circular dependencies
node_modules/readable-stream/lib/_stream_readable.js -> node_modules/readable-stream/lib/_stream_duplex.js -> node_modules/readable-stream/lib/_stream_readable.js
node_modules/readable-stream/lib/_stream_duplex.js -> node_modules/readable-stream/lib/_stream_writable.js -> node_modules/readable-stream/lib/_stream_duplex.js
polyfill-node._stream_duplex.js -> polyfill-node._stream_readable.js -> polyfill-node._stream_duplex.js
polyfill-node._stream_duplex.js -> polyfill-node._stream_writable.js -> polyfill-node._stream_duplex.js

See discussion in #32.