Fix: Make markdown2html more robust
Fix: Make markdown2html more robust

markdown lib can not handle "undefined" input values
Huggle77/4minitz,4minitz/4minitz,4minitz/4minitz,RobNeXX/4minitz,Huggle77/4minitz,Huggle77/4minitz,RobNeXX/4minitz,RobNeXX/4minitz,4minitz/4minitz