Improve Address test coverage

cmd/geth, jsre: improve the js command

cmd/bootnode: fix -genkey, add logging options

geth js stopped the JS runtime after running the first input file
and blocked for pending callbacks. This commit makes it process
all files and enables quitting with Ctrl-C regardless of callbacks.

Error reporting is also improved. If a script fails to load, the error
is printed and includes the backtrace. package jsre now ensures that
otto is aware of the filename, the backtrace will contain them.

Before:

$ geth js bad.js; echo "exit $?"
... log messages ...
exit 0

After:

$ geth js bad.js; echo "exit $?"
... log messages ...
Fatal: JavaScript Error: Invalid number of input parameters
    at web3.js:3109:20
    at web3.js:4917:15
    at web3.js:4960:5
    at web3.js:4984:23
    at checkWork (bad.js:11:9)
    at bad.js:19:1

exit 1

rpc: remove NotifierContextKey

rpc: move web3.js extensions to internal/web3ext

Context keys must have a unique type in order to prevent
any unintented clashes. The code used int(1) as key.

Fix it by implementing the pattern recommended by package context.

accounts/abi/bind/backends: estimate needed gas, not used

all: fix go vet warnings

whisper: deflake Test*MessageExpiration

These tests have become a common annoyance on CI. Fix them by allowing
messages with expiration == now into the cache and delaying the check
for expired message handling slightly.

Lazy "I'll just put return here instead of fixing the test" found by go vet.

logging.printf triggered a format string warning. Silence it
by renaming the function.

This fixes a few uses of unkeyed Body literals which go vet was
complaining about.

all: update license information

cmd/utils: strip excessive whitespace from api command line arguments

eth: fix single transaction tracing (run prev mutations)

eth: add chaindbProperty to debug API (+ console fixes)

This makes web3 internals like _requestManager invisible.

accounts: disable filesystem notifications on iOS

jsre: print BigNumber objects with custom constructor as number

cmd/utils: fix accounts merge error on console unlock