Boss for LearnDash 1.0.7

* Tweak – Various layout updates
* Tweak – Check if LearnDash is installed and activated
* Tweak – Check if Boss theme is installed and activated
* Fix – Sidebar is missing on topics pages
* Fix – Category link in group different from link in course
* Fix – LearnDash custom labels compatibility
* Fix – Lesson meta info (topics count and lesson time) added to single course
* Fix – All lessons have 1 topic assigned by default, even when none assigned
* Fix – Expand/Collapse All lesson link added
* Fix – Course tab added to single course page
* Fix – Course group extension