[ENH] Tiki Calendar : Fix undefined indexes customurl, customfgcolor, custombgcolor
When calendarId ($_REQUEST['calendarId']) doesn't exist (the calendar doesn't exist) the info variable doesn't have some indexes. So before getting calendar information, we have to check if the calendarId exists, if not the info variable will be initialized with default values. Related task (GlitchTip error 1, error 2, error 3, error 4).
Edited by Jean-Marc Kadimba