Dependency upgrades

[MatthewHerbst]

Upgrade our dependencies to their latest versions. Steps:

1. Manually upgraded all listed dependencies
2. Ran npm audit fix to correct audit issues
3. Ran npm dedupe to reduce dependency bloat

Also fixed a small bug in the local example.

Build before changes:

Hash: 2627e4d377305a147709
Version: webpack 4.29.6
Time: 1373ms
Built at: 08/06/2019 4:36:20 PM
     Asset       Size  Chunks             Chunk Names
index.d.ts  865 bytes          [emitted]
  index.js   10.9 KiB       0  [emitted]  main
Entrypoint main = index.js
[0] ./src/index.tsx 7.74 KiB {0} [built]

Build after changes:

Hash: db0099965a1b3a7069de
Version: webpack 4.39.1
Time: 1656ms
Built at: 08/06/2019 4:35:13 PM
     Asset      Size  Chunks             Chunk Names
index.d.ts  1.02 KiB          [emitted]
  index.js  10.9 KiB       0  [emitted]  main
Entrypoint main = index.js
[0] ./src/index.tsx 7.74 KiB {0} [built]