required changes for the gateway

[ya7ya]

These are the required changes requested by @dignifiedquire in #968

UDPATE: I just noticed @victorbjelkholm requested changes, I'll implement them and push them to this branch as well.

Changes:

• use slice instead of splice

• remove noop since promisify always defines a callback

• use async reduce instead of eachOfSeries

• no duplicate logging + returning error

• smallCamelCase for non-constructors

• fix indentations

• use callbacks instead of promises.

• use pull.through instead of pull.drain so response isn't completely held in memory before responding

• use switch since there are too many conditions to check

• use templating engine. (still in discussion, no clear decision yet. Let me know when you guys decide)

• internal cat with pull streams for efficiency. (outside the scope of this feature. but a very cool idea that I think we should have)

Please Let me know if there are any other changes required. Thanks for your help 👍

[daviddias]

use templating engine. (still in discussion, no clear decision yet. Let me know when you guys decide)

I'm fine with doing as it is for now and adding that to a separate issue.

internal cat with pull streams for efficiency. (outside the scope of this feature. but a very cool idea that I think we should have)

This will be the focus of js-ipfs 0.27 -> ipfs-inactive/interface-js-ipfs-core#126

[daviddias]

Some of these addrs are not required. I'll fix it in the main PR.