Update for 5.0 branch to teachPress 5.0-beta. This is a sync with GitHub repository: https://github.com/winkm89/teachPress/commit/d3a4c2f503fe252799d8deec436d84c921988db7

git-svn-id: https://plugins.svn.wordpress.org/teachpress/branches/5.0.x@1039395 b8457f37-d9ea-0310-8a92-e5e31aec5664