Upgrade dependencies, including http and hyper, where possible.

[ozabalaferrera]

Description

This PR is the result of the discussion in #227. It upgrades various dependencies, including http and hyper, to the latest versions.

Status

This PR is ready for review. I worked on this sporadically, so I am sure there are better ways to accomplish some of what I did here.

Excluded

warp and actix have not been upgraded to http v1; I found it difficult to convert between types or implement traits. Therefore, those bindings here are mostly unchanged. I also created a separate feature flag for the old http v0.2.

Testing

I ran all the commands on the contributing guide. I also ran cargo test --all --features with all the features individually.