feat: Add offset/length arguments to files.cat

[achingbrain]

Adds offset/length args to ipfs-api.

See:

• feat: Allow ipfs.files.cat to return slices of files ipfs/js-ipfs#1231
• doc: Documents the offset/length arguments to ipfs.files.cat and friends interface-js-ipfs-core#242
• chore: Conform to spec for stream slices js-ipfs-unixfs-engine#209

[daviddias]

@achingbrain can you check on why CI is failing terribly ?

[achingbrain]

@diasdavid It's looking slightly healthier now but will need the fixes from #746 and ipfs-inactive/interface-js-ipfs-core#258

I encountered some problems with duplicated dependencies while working on multiple libraries simultaneously and ~ and ^ are used interchangeably. Do you think we could standardise on one or the other across all js-ipfs projects? Better yet, can we release v1 of all modules that are currently 0.x?

[daviddias]

I encountered some problems with duplicated dependencies while working on multiple libraries simultaneously and ~ and ^ are used interchangeably. Do you think we could standardise on one or the other across all js-ipfs projects? Better yet, can we release v1 of all modules that are currently 0.x?

Our rule is: Use ~ for everything below 1.0.0 and ^ for everything above 1.0.0. If you find a package.json that is not following this rule, please submit a PR.

As for v1 of all the modules. We've discussed it in the past and agreed that until IPFS reaches 1.0.0, we won't be releasing 1.0.0 modules.

[achingbrain]

until IPFS reaches 1.0.0, we won't be releasing 1.0.0 modules

What's stopping IPFS from reaching v1?

[daviddias]

Many things -- https://github.com/ipfs/ipfs/blob/master/ROADMAP-TO-1.0.0.md --, the first questions should be, what is missing to reach Beta, see ipfs/ipfs#314