Update dependencies to make the package work with latest node/io

[yamalight]

Update of the dependencies to make the package work with latest node/io (v3.x and v4.x).
Will close #110

[dlongley]

Unfortunately, jsdom 4.0+ doesn't work with node 0.10 or node 0.12. Until we separate the RDFa parser from this package (which we should, see: #98), we can't upgrade jsdom past 3.x.

[yamalight]

@dlongley why not publish it as next major version and backport fixes (which would be trivial since difference is only in deps versions) when needed to older version? (e.g. 0.3.x for pre 3.0 and 0.4.x for 3.0+)

[dlongley]

@yamalight, I was holding out hope to cut the RDFa stuff out entirely before jumping to the next version. That way we only have to deal with two versions instead of three ... as we'll have to bump versions again once we move RDFa support to a separate package. We may do that (what you suggest) anyway, because we haven't had time (and there have been no PRs) to split RDFa out of the package in a long while.

[yamalight]

@dlongley did I get it correctly that the only part that uses RDFa is jsonld.request = require('./request');? If yes, then it should be pretty easy to split that into separate optional module, right? If not, I'll dig in a bit more tomorrow.

If this split will speed up the update to 4.0.0, I'm willing to do this over tomorrow and send a PR, since we're depending on this module too much :)

[dlongley]

@yamalight, I'm going to cc @davidlehn to provide more details on splitting stuff out. Since he worked on the RDFa integration stuff he'll have a better idea of how easy it should be than me.

[davidlehn]

I split request extension into https://github.com/digitalbazaar/jsonld-request and cli tool into https://github.com/digitalbazaar/jsonld-cli. If you just need to use core jsonld lib, this may fix dependency issues.

[yamalight]

@davidlehn yep, works great now, thanks!
I'll close the PR since it's not needed anymore.