Updates and adds some package docs.
It also provides autogenerated README's using https://github.com/jimmyfrasche/autoreadme tool. To use it, make sure it's installed on your system, and every time you update documentation, run go generate to update the README.md file.
This PR adds Fetch API and fixes#289 by using concurrency safe Otto VM wrapper wherever it's possible. This involves new package geth/jail/vm that is used by jail and by our forked ottoext/{fetch/timers/loop} packages.
It also adds more tests that are supposed to be run with --race flag of go test.
Adrià Cidre
Ivan Daniluk