PRESENCE: fixing present-check-interval to be equal like regular check-interval if it's not set


git-svn-id: svn://svn.code.sf.net/p/fhem/code@4824 2b470e98-0d58-463d-a4d8-8e2adae1ed80
dokumentation repaired

git-svn-id: svn://svn.code.sf.net/p/fhem/code@4825 2b470e98-0d58-463d-a4d8-8e2adae1ed80