added id and label element to chekbox
module classroom first commit: venues and classrooms insert, update and delete
html table generatione moved to BaseHtmlLib::tableElement
minor improvements to classrooms managing
added ajax form for managing venues
added service type field
added duration_hours property to Course and CourseInstance objects
added tables PREFIX where needed
added $id_venue to classroom_getClassroom method
added classroomAPI class to talk with other modules
module classagenda initial commit

front-end functionalities almost fully implemented
completed the classagenda module calendar feature
removed unneeded require statements
calendar feature bug fix and improvements
added active instances filter to class calendar page
added new getAllVenuesWithClassrooms method
minor enhancement for getJoined method
added doc and code comments
Merge branch 'master' into module-classroom
removed comment