Investigate improving performance

[addyosmani]

We're interactive in about 5.5-6s atm https://www.webpagetest.org/video/compare.php?tests=170427_80_cf5615014847b5d933363cb99ef6ea3e-r:1-c:0

Already using code-splitting. I'll investigate if we can get any further with preloading critical chunks or golfing down things that aren't needed.

[addyosmani]

Okay 🥁 roll.

We were previously getting interactive in about 7.7s on WPT with EM https://www.webpagetest.org/result/170427_80_cf5615014847b5d933363cb99ef6ea3e/

and with preload support now live we're down to 5.3s.
https://www.webpagetest.org/result/170427_2Z_9881280876310ac702179ccebfbacb68/

However, when looking closer at the trace in this case it hasn't really made a huge practical difference even if the metrics say it has. Still..at least hitting FP sooner.

[addyosmani]

x-ref: adddf27