Medea Destiny in-world; dialog

Medea says: "<512 not <513 for dialog message length. AAAARGH. *bangs
head against wall*"

This fixes #76
re-added missing attributions and changelog

The script was missing attributions which must have been lost while work
was done on it in-world; this script was originally created by WhiteFire
Sondergaard based on the plugin template at the time by Cleo Collins.
Kadah Coba, Satomi Ahn and various others contributed improvements and
patches to this script.
WhiteFire Sondergaard in-world; keyholder

WhiteFire: "Fixed the refactoring in UserCommand() so it actually works
with buttons from foreign menus."
Jean Severine in-world; leashParticle

this commit ads a "life" menu function for the particle engine for
leashes
rolling back realtime feature

for the next beta version we want the broken feature back inside to be
able running more tests; I believe the problem is fixed with the updated
keyholder script by WhiteFire Sondergaard
BETA channel init

so instead of a seperated branch lets try having the "beta channel" just
as a folder; included are version and news item as well as the update
script so we won't have to edit the url each time in the "main channel"
update script
beta urls and current slurls
version from card instead string

this is kinda a test if we get the version number in the main menu
properly fetched from the card; I used to always put it in the string at
line 25 each update to work around the problem described in #26 but that
didn't really solve it; Medea wrote the parts to have the version number
fetched from the card and recommended to put something like "fetching"
or "loading" lets see if it works!
BETA 3.951 ready to ship
Merge pull request #20 from OpenCollar/main

pull from OC main, get ready for beta