use shikaka as library bundler, fix tests

[StarpTech]

This PR simplifies the bundling process. I also fixed the test suite. This should fix #5 Therefore https://github.com/StarpTech/shikaka use browserlist property to determine the polyfills.

The package size was reduced from 4KB to 2.21 KB (gzip)

$ shikaka src/index.js --format es --format cjs --minify --sourcemap
Build ES output to dist:
      5.77 KB  es/index.js
Build CJS output to dist:
      5.84 KB  cjs/index.js
Done in 2.84s.