/**
 * @page tutorial The Tutorial
 *
 * @section introduction Introduction
 *
 * Before inserting ssh hooks into your programs, you must know some basics
 * about the ssh protocol, and understand why the ssh library must implement
 * them. Lot of the protocols specifications are hidden by the ssh library API
 * (of course !) but some still needs an attention from the end-user
 * programmer. Note that libssh is still an alpha product, and the API may vary
 * from one version to another. The only guess I can make is that the API won't
 * radically change.
 *
 * The SSH protocol was designed for some goals which I resume here :
 *
 *   - Privacy of data
 *   - Security
 *   - Authentication of the server
 *   - Authentication of the client
 *
 * The client MUST be sure who's speaking to before entering into any
 * authentication way. That's where the end programmer must ensure the given
 * fingerprints *are* from the legitimate server. A ssh connection must follow
 * the following steps:
 *
 *  - Before connecting the socket, you can set up if you wish one or other
 *  server public key authentication ie. DSA or RSA. You can choose
 *  cryptographic algorithms you trust and compression algorithms if any.
 *
 *  - The connection is made. A secure handshake is made, and resulting from
 *  it, a public key from the server is gained. You MUST verify that the public
 *  key is legitimate.

 *  - The client must authenticate : the two implemented ways are password, and
 *  public keys (from dsa and rsa key-pairs generated by openssh). It is
 *  harmless to authenticate to a fake server with these keys because the
 *  protocol ensures the data you sign can't be used twice. It just avoids
 *  man-in-the-middle attacks.
 *
 *   - Now that the user has been authenticated, you must open one or several
 *   channels. channels are different subways for information into a single ssh
 *   connection. Each channel has a standard stream (stdout) and an error stream
 *   (stderr). You can theoretically open an infinity of channel.
 *
 *   - With the channel you opened, you can do several things :
 *     - Open a shell. You may want to request a pseudo virtual terminal before
 *     - Execute a command. The virtual terminal is usable, too
 *     - Invoke the sftp subsystem. (look at chapter 6)
 *     - invoke your own subsystem. This is out the scope of this document but it is easy to do. 
 *
 *   - When everything is finished, just close the channels, and then the connection. 
 *
 * At every place, a function which returns an error code (typically -1 for int
 * values, NULL for pointers) also sets an error message and an error code. I
 * high-lined the main steps, now that's you to follow them :) 
 *
 * @section setup Creating the session and setting options
 *
 * TODO
 *
 * @section connect Connecting to the server
 *
 * TODO
 *
 * @section auth Authentication
 *
 * TODO
 */