Use fast greedy mesher. Closes GH-10
Add game mode toggle creative/survival. Closes GH-11

Press 'C' to toggle between survival (default) and creative,
currently only disables/enables double-tap fly mode.

Requires https://github.com/deathcap/voxel-fly/commit/62cfda2dfedbfc227a2dd33f7b5ecad3e2af5306
Add publish to package.json scripts

Run with: npm run-script deploy
Regenerate bundle.js using deploy.sh