util.stanza: add at_top helper
This allows the user to detect whether the cursor is currently
at the top of the stanza. This will be used by util.xmppstream
to be able to port it over.
# Prosody IM Server
## Description
Prosody is a server for Jabber/XMPP written in Lua. It aims to be easy
to use and light on resources. For developers, it aims to give a
flexible system on which to rapidly develop added functionality or
rapidly prototype new protocols.
## Useful links
Homepage: https://prosody.im/
Download: https://prosody.im/download
Documentation: https://prosody.im/doc/
Issue tracker: https://issues.prosody.im/
Jabber/XMPP Chat:
Address:
prosody@conference.prosody.im
Web interface:
https://chat.prosody.im/
Mailing lists:
User support and discussion:
https://groups.google.com/group/prosody-users
Development discussion:
https://groups.google.com/group/prosody-dev
## Installation
See the accompanying INSTALL file for help on building Prosody from source. Alternatively
see our guide at https://prosody.im/doc/install