* les: fix light fetcher database race

* les: lightFetcher comments

vendor: update rjeczalik/notify so that it compiles on go1.10

p2p/discover: validate bond against lastpong, not db presence

I forgot to change the check in udp.go when I changed Table.bond to be
based on lastPong instead of node presence in db. Rename lastPong to
bondTime and add hasBond so it's clearer what this DB key is used for
now.

* swarm: added script to HTML header to create favicon addresses #153

* swarm: moved data blob direclty into link tag, removed script

* swarm: added favicon info to other html templates

* swarm: fixing test errors

* swarm: fixing favicon test

* swarm: fixing travis tests

* swarm: added script to HTML header to create favicon addresses #153

* swarm: moved data blob direclty into link tag, removed script

* swarm: added favicon info to other html templates

* swarm: fixing test errors

* swarm: fixing favicon test

* swarm: fixing travis tests

This is in preparation for the switch to libp2p: the ID generated
will be from a private key created with the help of libp2p's crypto
library, while Whisper will still use Go's default crypto libraries
for encrypting its messages. This change removes a conflict.

It shouldn't have any impact as the person receiving emails is
the user, not the node.

* whisper: timeout extended

* whisper: test updated

* whisper: test updated

les: add missing lock around peer access

main: add gc flags to import-command

- according to implementation of `IntrinsicGas`
we can continue execution since problem will be detected
later. However, early return is future-proof for changes.

p2p/discover: fix out-of-bounds issue

* travis.yml: work around Go 1.9.4 issue

* travis: workaround the workaround

Talk about "state" instead of "trie timing", "trie memory" and remove
the overzealous warning when the limit is just reached. Since the time
limit is always reached on slow machines, move the message to info level
so users don't freak out about internal details.

cmd/puppeth: unify discv4 and discv5 ports

node, rpc: fix linter issues

* cmd,node,rpc: add allowedHosts to prevent dns rebinding attacks

* p2p,node: Fix bug with dumpconfig introduced in r54aeb8e4

* rpc: add wildcard support for rpcallowedhosts + go fmt

* cmd/geth, cmd/utils, node, rpc: ignore direct ip(v4/6) addresses in rpc virtual hostnames check

* http, rpc, utils: make vhosts into map, address review concerns

* node: change log messages to use geth standard (not sprintf)

* rpc: fix spelling

* p2p: add DialRatio for configuration of inbound vs. dialed connections

* p2p: add connection flags to PeerInfo

* p2p/netutil: add SameNet, DistinctNetSet

* p2p/discover: improve revalidation and seeding

This changes node revalidation to be periodic instead of on-demand. This
should prevent issues where dead nodes get stuck in closer buckets
because no other node will ever come along to replace them.

Every 5 seconds (on average), the last node in a random bucket is
checked and moved to the front of the bucket if it is still responding.
If revalidation fails, the last node is replaced by an entry of the
'replacement list' containing recently-seen nodes.

Most close buckets are removed because it's very unlikely we'll ever
encounter a node that would fall into any of those buckets.

Table seeding is also improved: we now require a few minutes of table
membership before considering a node as a potential seed node. This
should make it less likely to store short-lived nodes as potential
seeds.

* p2p/discover: fix nits in UDP transport

We would skip sending neighbors replies if there were fewer than
maxNeighbors results and CheckRelayIP returned an error for the last
one. While here, also resolve a TODO about pong reply tokens.

core: force import known but rolled back blocks

build: deprecate zesty, add bionic PPA

eth: only disable fast sync after success

eth/downloader: don't require state for ancestor lookups