updated procedure for floorplan-specific icons

git-svn-id: svn://svn.code.sf.net/p/fhem/code@4634 2b470e98-0d58-463d-a4d8-8e2adae1ed80
- attribut keepDeviceAlive added
- function RandomTimer_Wakeup() added

git-svn-id: svn://svn.code.sf.net/p/fhem/code@4635 2b470e98-0d58-463d-a4d8-8e2adae1ed80