Update development dependencies

[oriondean]

We should look at investigating updating our development dependencies to see what benefits it would provide

[stevenjob]

rollup 😃

[sh1989]

This may help https://medium.com/webpack/webpack-and-rollup-the-same-but-different-a41ad427058c

[ryanggrey]

Is this issue intended as a "update existing dev dependency versions" or a "review and migrate current build tools"?

[oriondean]

review and migrate current build tools

[ryanggrey]

Possible updates:

• Migrate from browserify to rollup #72
• Migrate to using selenium-webdriver directly #67
• Migrate to using only npm dev scripts #66

[ryanggrey]

#91