Content-Disposition is only used for communicating the filename. It does
not need to be stored in the database as we have upload_name anyway. It
does not need to be in types.MediaMetadata and does not need to be
logged.

Reorder functions to have public API functions in alphabetical order at
the top, internal package functions at the bottom in call order.

Use RawURLEncoding to avoid padding the hash with '='.

Use stronger types for paths in public API.

Simplify comments.

Skeleton for the Media API

Content-Disposition is not a valid request header and so it must be
evaluated from the upload request's filename query parameter.

Clearer that it's a map from mxc URLs to sync.Cond

* 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

- Renamed `clientapi/auth/types` to `clientapi/auth/authtypes` for the same
  horrible namespace clashing reasons as `storage`.
- Factored out `makeAPI` to `common`.
- Added in `makeAuthAPI`.

Previously, all database stuff was under the helpfully named
package 'storage'. However, this convention is used throughout all
of dendrite, which will clash the moment we want to add auth to all
the CS API endpoints. To prevent the package name clash, add
sub-directories which represent what is being stored so the final
usage ends up being:

```
func doThing(db *storage.SyncServerDatabase, authDB *accounts.Database)
{
    // ...
}
```

* Start implementing the federation server keys API.

* Fix copyright

* Fix comments

* Comment on the key format

* Better explain what the ValidityPeriod is

* Return a 200 status code

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

* Rename "make" to "makeAPI" and factor out some more common code into it

Naming a function the same as a go builtin function seems like a bad
idea. Also move the call to `NewJSONRequestHander` inside the function
rather than calling it everywhere.

* Fix typo

.travis.yml: Bump golang to 1.8

- `s/Server/OutputRoomEvent/` in `consumers` to accurately reflect what is being consumed.
- `s/set/userIDSet/` in `notifier.go` for clarity.
- Removed lying comments.

* Add test for transition to leave

* Add test for join/leave in the same /sync response

The logic required to populate the right bits of `RoomData` tends towards
the complete `/sync` response struct, so just use the actual response struct
and save the hassle of mapping between the two. It may not make much difference
in its current form, but the next PR will make use of this.

This PR has no functional changes.

This is only 'mostly' correct currently, because what should be no-op dupe
joins will actually trigger the entire room state to be re-sent.

Bizarrely, it's significantly easier to just do that than work out if we should,
and there are no client-visible effects to doing so, so we just do it for now.