Released version 1.1 (approved version, thx to "Jonny got his gun")
I implemented the ideas from juKay, but I rewrote the code on my own (implemented it with less cpu-usage needed in most cases).
ATTENTION: ALL CVARS CHANGED NAME. juKay was right with his suggestion about mp_cvars. I took the same names as juKay, only afk_time was to bad, I choosed afk_kicktime as there is also afk_slaytime in my version.
Some additional cvars.
Changelog 1.1
afk_kicktime -- cvar changed name
afk_minplayers -- cvar changed name
afk_slaytime -- new cvar
afk_slayplayers -- new cvar
afk_adminimmunity --new cvar
Read man to know what the cvars are for.
These cvars shall give you the possibility to configure this plugin differently for each map.