Refactor and clean up Jail package:
Removes account.Manager and txqueue.Manager from Jail as they are not used anymore
Removes messageID related code from Jail.Send
Simplifies Jail.Send to be a wrapper around RPC client's CallRaw
Renames jail_cell* to cell*
Related cleanups
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.