MQTT: refactor to get rid of 'constant subroutine redifined'-messages caused by import of Net::MQTT

git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@6653 2b470e98-0d58-463d-a4d8-8e2adae1ed80
57_Calendar: deal with non-existent end times

git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@6654 2b470e98-0d58-463d-a4d8-8e2adae1ed80
57_Calendar: calendar event anymore in modeAlarmed if started

git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@6655 2b470e98-0d58-463d-a4d8-8e2adae1ed80
MAINTAINER.txt: support forum adjusted for Calendar and Weather

git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@6656 2b470e98-0d58-463d-a4d8-8e2adae1ed80
59_Weather: change icon for condition clear to sunny.png

git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@6657 2b470e98-0d58-463d-a4d8-8e2adae1ed80