* build: use golangci-lint

This changes build/ci.go to download and run golangci-lint instead
of gometalinter.

* core/state: fix unnecessary conversion

* p2p/simulations: fix lock copying (found by go vet)

* signer/core: fix unnecessary conversions

* crypto/ecies: remove unused function cmpPublic

* core/rawdb: remove unused function print

* core/state: remove unused function xTestFuzzCutter

* core/vm: disable TestWriteExpectedValues in a different way

* core/forkid: remove unused function checksum

* les: remove unused type proofsData

* cmd/utils: remove unused functions prefixedNames, prefixFor

* crypto/bn256: run goimports

* p2p/nat: fix goimports lint issue

* cmd/clef: avoid using unkeyed struct fields

* les: cancel context in testRequest

* rlp: delete unreachable code

* core: gofmt

* internal/build: simplify DownloadFile for Go 1.11 compatibility

* build: remove go test --short flag

* .travis.yml: disable build cache

* whisper/whisperv6: fix ineffectual assignment in TestWhisperIdentityManagement

* .golangci.yml: enable goconst and ineffassign linters

* build: print message when there are no lint issues

* internal/build: refactor download a bit

* dashboard, p2p: visualize peers

* dashboard: change scale to green to red

* cmd, dashboard: remove custom assets, webpack dev server

* dashboard: yarn commands, small fixes

- added a case error struct that contains information about certain error cases
in which we would like to output more information to the client
- added a validation method that iterates and adds the information that is
stored in the error cases

* dashboard: footer, deep state update

* dashboard: resolve asset path

* dashboard: remove bundle.js

* dashboard: prevent state update on every reconnection

* dashboard: fix linter issue

* dashboard, cmd: minor UI fix, include commit hash

* remove geth binary

* dashboard: gitCommit renamed to commit

* dashboard: move the geth version to the right, make commit optional

* dashboard: commit limited to 7 characters

* dashboard: limit commit length on client side

* dashboard: run go generate

* dashboard: minor design change

* dashboard: Flow integration, message API

* dashboard: minor polishes, exclude misspell linter

* cmd, dashboard: dashboard using React, Material-UI, Recharts

* cmd, dashboard, metrics: initial proof of concept dashboard

* dashboard: delete blobs

* dashboard: gofmt -s -w .

* dashboard: minor text and code polishes

This commit converts the dependency management from Godeps to the vendor
folder, also switching the tool from godep to trash. Since the upstream tool
lacks a few features proposed via a few PRs, until those PRs are merged in
(if), use github.com/karalabe/trash.

You can update dependencies via trash --update.

All dependencies have been updated to their latest version.

Parts of the build system are reworked to drop old notions of Godeps and
invocation of the go vet command so that it doesn't run against the vendor
folder, as that will just blow up during vetting.

The conversion drops OpenCL (and hence GPU mining support) from ethash and our
codebase. The short reasoning is that there's noone to maintain and having
opencl libs in our deps messes up builds as go install ./... tries to build
them, failing with unsatisfied link errors for the C OpenCL deps.

golang.org/x/net/context is not vendored in. We expect it to be fetched by the
user (i.e. using go get). To keep ci.go builds reproducible the package is
"vendored" in build/_vendor.

The new build script, ci.go, replaces some of the older shell scripts.
ci.go can compile go-ethereum, run the tests, create release archives
and debian source packages.

Many people need or want to build go-ethereum from the git repository,
mostly to stay up to date with recent changes. We cannot expect that
people without Go experience grok the Go workspace concept.

With the Makefile, building from github requires only
three steps (provided that a Go toolchain is installed):

    - git clone https://github.com/ethereum/go-ethereum
    - ... install C libraries (libgmp, etc.) ...
    - make

dockers locally

cppjit client (python not yet working)

* Add new generic key_store interface
* Add new plaintext key store storing unprotected keys on disk
* Add new encrypted key store storing encrypted keys on disk
* Add new entropy mixing function using OS and go runtime sources

and virtualbox

Converted to npm package
Added brower
Added browserify with minification
Updated Readme