Omit replies for RPC notification requests

When Id is missing, the client does not want a response

core: changed log message for forks. closes #952

Format contract code as hexdata

Check for error on DB fetch of tx

cmd/geth: use plain keystore for JS tests

This reduces the time it takes to run the tests back to 3 seconds.

eth, eth/downloader: handle a potential unknown parent attack

p2p: tweak connection limits

This should increase the speed a bit because all findnode
results (up to 16) can be verified at the same time.

The returned reason is currently not used except for the log
message. This change makes the log messages a bit more useful.
The handshake code also returns the remote reason.

Introduced default unlock duration when an account is unlocked from t…

p2p/nat: fix UPnP auto discovery

Make read of ethash hashrate atomic and update ethash godep

eth/downloader: fix deliveries to check for sync cancels

removed invalid filename characters

Some of the dependencies use package log. This change ensures that the
log output looks uniform and respects glog flags.

People stil get confused about the messages. This commit changes
the levels so that the only thing printed at the default level (info)
is a successful mapping.

Created separate family and ancestors environment objects

The test listens for multicast UDP packets on the default interface
because I couldn't get it to work reliably on loopback without massive
changes to goupnp. This means that the test might fail when there is a
UPnP-enabled router attached on that interface. I checked that locally
by looping the test and it passes reliably because the local SSDP server
always responds faster.

Concurrent calls to Interface methods on autodisc could return a "not
discovered" error if the discovery did not finish before the call.
autodisc.wait expected the done channel to carry the found Interface
but it was closed instead.

The fix is to use sync.Once for now, which is easier to get right.
And there is a test. Finally.

This will have to change again when we introduce re-discovery.

On the test network, we've seen that it becomes harder to connect
if the queues are so short.

p2p/discover: fix out-of-bounds slicing for chunked neighbors packets

The code assumed that Table.closest always returns at least 13 nodes.
This is not true for small tables (e.g. during bootstrap).