* fix: performance bottleneck in stat.js (#463)
Array.shift seems to be very slow, perhaps linear, on some
engines, resulting in _update consuming a lot of CPU.
* docs(fix): correct docs and example for pnet (#464)
* docs(fix): correct docs and example for pnet
* docs(fix): correct pnet docs
* docs(fix): update README.md language (#468)
* docs: reciprocate (#474)
* docs(example): fix ipfs cat (#475)
`ipfs.files.cat` is incorrect. the correct function is `ipfs.cat`
* fix: async await examples/echo
* fix: examples readme typos (#481)
* fix: simplify libp2p bundle for echo example
* docs: update chat example and add info to its readme
* docs: update echo example
* docs: update libp2p in browser example
* docs: update pubsub example
* docs: update peer and content routing examples
* docs: update discovery mechanisms example
* docs: update encrypted comms example
* docs: update protocol and stream muxing example
* feat: add config validation
* test: update CI configs, use only node 8
