* Update gometalinter config

gometalinter now uses `maligned` instead of `aligncheck`
(https://github.com/alecthomas/gometalinter/pull/367), so we need to update our
config accordingly.

* Update gometalinter

* Disable gotype linter

gotype does not seem to play nicely with the gb vendor directory. In
particular, it wants each of our dependencies to be built and installed (see
https://github.com/golang/go/issues/10969), but (empirically) it will not
accept them being installed in `pkg` but insists on them being in `vendor/pkg`.

This presents a problem because `gb build` builds the packages into `pkg`
(which doesn't seem entirely unreasonable since `.` comes before `vendor` in
`$GOPATH`). `go install github.com/x/y` does install in `vendor/pkg` but
requires us to know the name of each package.

The general conclusion of https://github.com/alecthomas/gometalinter/issues/91
seems to have been that the easiest thing to do is to disable `gotype` for now.

* Fix `unparam` lint

* Fix goshadow lint

gb vendor update github.com/matrix-org/gomatrixserverlib
gb vendor update github.com/matrix-org/util

* Implement shared secret registration

* Use HexString from gomatrixserverlib

* Correctly check username validility

* Use a read-only snapshot transaction for calculating sync responses

* gb vendor update github.com/lib/pq

* Make media repo use error rather than jsonErrorResponse

* Update comments

* gb vendor github.com/pkg/errors

* Fixup error formats

* Add context.Context to the federation client

* gb vendor update github.com/matrix-org/gomatrixserverlib

* Add comment

* gb vendor update github.com/matrix-org/gomatrixserverlib

* Add handler for the exchange_third_party_invite endpoint

* Doc

* Use SendEvents to send the invite to the roomserver

* Add missing error check

* Add checks

* Fix response to /invite to match the format expected by synapse

* gb vendor update github.com/matrix-org/gomatrixserverlib

* Use gomatrixserverlib.RespInvite

* gb vendor update github.com/matrix-org/gomatrixserverlib

* Add missing file headers

* Move the ID server's signatures verification to common

* Allow verification without specifying a server name

* Add third-party structs to membership events content

* Add processing of 3PID onbind requests

* Use reference for third party invite data

* Fix return arguments order

* Revert "Move the ID server's signatures verification to common"

This reverts commit 93442010316ce71a77ac58ffd3613754ce8fe969.

* Revert "Allow verification without specifying a server name"

This reverts commit fd27afbf82eac50fe9f7b83b26cfce3c66d530d2.

* Remove checks that are already occurring in gomatrixserverlib

* Change return type of createInviteFrom3PIDInvite

* Add doc, add checks in fillDisplayName

* Use MakeFedAPI

* Invert condition

* Use AuthEvents to retrieve the 3PID invite

* Update comment

* Remove unused parameter

* gb vendor update github.com/matrix-org/gomatrixserverlib

* Use utility methods from gomatrixserverlib, rather than reimplementing them

* Return string rather than pointer to string

* Update gomatrixserverlib

* Add a database for storing the server keys

* Tweak wording, and comment on the resolution of the timestamp

* Update gomatrixserverlib

* vendor: Add bimg image processing library

bimg is MIT licensed. It depends on the C library libvips which is LGPL
v2.1+ licensed. libvips must be installed separately.

* mediaapi: Add YAML config file support

* mediaapi: Add thumbnail support

* mediaapi: Add missing thumbnail files

* travis: Add ppa and install libvips-dev

* travis: Another ppa and install libvips-dev attempt

* travis: Add sudo: required for sudo apt* usage

* mediaapi/thumbnailer: Make comparison code more readable

* mediaapi: Simplify logging of thumbnail properties

* mediaapi/thumbnailer: Rename metrics to fitness

Metrics is used in the context of monitoring with Prometheus so renaming
to avoid confusion.

* mediaapi/thumbnailer: Use math.Inf() for max aspect and size

* mediaapi/thumbnailer: Limit number of parallel generators

Fall back to selecting from already-/pre-generated thumbnails or serving
the original.

* mediaapi/thumbnailer: Split bimg code into separate file

* vendor: Add github.com/nfnt/resize pure go image scaler

* mediaapi/thumbnailer: Add nfnt/resize thumbnailer

* travis: Don't install libvips-dev via ppa

* mediaapi: Add notes to README about resizers

* mediaapi: Elaborate on scaling libs in README

* Start implementing the join room API

* Hacks to get join room working

* Make the TLS fingerprint configurable

* Fix the client API proxy to handle '#' correctly

* Return a 200 OK response

* Write the join event along with current state to the room server

* Comment on the error handling

* Fix typos

* Fix tab

* Add TODO for moving authEventIDs to gomatrixserverlib

* Comment on why we ignore the key ID argument for local keys

* Avoid 'preceeded'

* Neaten the control flow

* Neaten the control flow even more

* Return pointers

* Rename err to lastErr for the loop

Including the ability to add new accounts with a user/password and
select accounts using a user/password. Uses bcrypt to hash passwords.

* Update gomatrixserverib dep

* Use helper functions when creating rooms

* Use gomatrixserverlib.StateKeyTuple

* Return the requested portions of current state in the query API

* Use Unique from github.com/matrix-org/util

* rewrite bulkSelectFilteredStateBlockEntries to use append for clarity

* Add test for stateKeyTupleSorter

* Replace current with a new StateEntryList rather than individually setting the fields