includes from cmake BINARY_DIR should be included before considering SOURCE_DIR

Document the encryption, and a few documentation issues are fixed

Rewrite the whole IID usage

IRC users and channels are now distinguished by the separator used in the
IID (% or !).

ref #2468

Add an <error/> element when the provided form is wrong, in two ad-hoc commands

Handle the 'cancel' ad-hoc action, and return an error for unsupported actions

ref #2521

Remove inactive ad-hoc sessions after a given time

ref #2521

Make the XMPP component port configurable

fix #2541

Add a TimedEvent to cancel the connection to a server after 5 seconds

Silence warnings coming from Botan headers

Properly search for libbotan even in a botan-1.11 subdirectory

Convert \n to <br/> in xhtml body

fix #2539

Give two supported compilers, as examples

Document the new optional libbotan dependency

Implement TLS support using Botan

For now, it tries two TLS ports and then connects to the non-tls port.  In
the future we would like the user to be able to configure that.

fix #2435

Little doc fix

Make the destructor of the SocketHandler class protected non-virtual

Update the documentation

Do not send an item-not-found presence from an invalid JID

Remove some unused function parameters names

Document the `admin` configuration option