Component could prevent updates propagating through render prop

[tapayne88]

Frustratingly, after reading this blog post https://cdb.reacttraining.com/react-inline-functions-and-performance-bdff784f5578 it looks like the shouldComponentUpdate optimisation I included in #21 will prevent prop changes propagating through to components within the render prop :(

[fkhadra]

Hey @tapayne88,

Thanks for the information. I'll read the article tonight. I also want to check if the intersection observer api is a good alternative.