* context: fixed documentation to be more specific about ContextKeyConn being the key for a gossh.ServerConn

Signed-off-by: Jeff Lindsay <progrium@gmail.com>

* server: fixes handler setup, changed to interface based handlers, added global request handler map

* tcpip: working remote forwarding

Signed-off-by: Jeff Lindsay <progrium@gmail.com>

* context: docs typo

Signed-off-by: Jeff Lindsay <progrium@gmail.com>

* session: always reply to unblock clients trying something

Signed-off-by: Jeff Lindsay <progrium@gmail.com>

* tcpip: stop listening when ssh clients disconnect

Signed-off-by: Jeff Lindsay <progrium@gmail.com>

* Remote forwarding (#87)

* Update generateSigner key size to 2048 (#62)

Fixes #58

* Add syntax highlighting to readme (#67)

* small api updates (#69)

These updates make it easier to implement and pass custom Session and
Context implementations

No compatibilty breaking, all tests pass

* Move channelHandlers to avoid data race (#59)

* Update tests to work with go 1.10+ (#73)

Fixes #72

* Update shutdown to use a WaitGroup rather than sleeping (#74)

* Fix race condition in TestServerClose (#75)

In test server close, 3 things need to happen in order:

- Client session start
- Server.Close
- Client session exit (With io.EOF)

This fix ensures the client won't do anything until after the call to
close which ensure's we'll get io.EOF rather than a different error.

* Update circleci config to test multiple go versions

* Update CircleCI config to test 1.9 and the latest

The x/crypto/ssh library dropped support go < 1.9 as that's the first
version to have the math/bits library.

https://github.com/golang/crypto/commit/83c378c48d6ee2ca9c20551b599aa74cb7765785

* Wait for connections to finish when shutting down

PR #74 introduced a WaitGroup for listeners, but it doesn't wait for
open connections before closing the server. This patch waits until all
conns are closed before returning from Shutdown.

*  Support port forwarding of literal IPv6 addresses (#85)

* Support port forwarding of literal IPv6 addresses

To disambiguate between colons as host:port separators and as IPv6 address separators, literal IPv6 addresses use square brackets around the address (https://en.wikipedia.org/wiki/IPv6_address#Literal_IPv6_addresses_in_network_resource_identifiers).  So host ::1, port 22 is written as [::1]:22, and therefore a simple concatenation of host, colon, and port doesn't work.  Fortunately net.JoinHostPort already implements this functionality, so with a bit of type gymnastics we can generate dest in an IPv6-safe way.

* Support port forwarding of literal IPv6 addresses

To disambiguate between colons as host:port separators and as IPv6 address separators, literal IPv6 addresses use square brackets around the address (https://en.wikipedia.org/wiki/IPv6_address#Literal_IPv6_addresses_in_network_resource_identifiers).  So host ::1, port 22 is written as [::1]:22, and therefore a simple concatenation of host, colon, and port doesn't work.  Fortunately net.JoinHostPort already implements this functionality, so with a bit of type gymnastics we can generate dest in an IPv6-safe way.

* Reverse port forwarding callback added

* garbage removed