Issue #110: file upload
Merge branch '3.3.x'
Merge branch 'issue/123_restrict_multiple_class_enrollments'
Merge branch '3.3.x'
Issue #110: Merge master and logo and upload logo file
Issue #110: creating, saving and visualizing pdf header variable
Issue #110: using pdf_header variable, changing variable directory
Issue #110: ignoring image dir
Issue #109: course name
Issue #109: edit course_name
Issue #110: renaming custom variable name to description