Some template and doc fixes
- Fixed #766 (agenda overview parent item look).
- Fixed #767 (Documentation sphinx bootstrap theme: html header)
- Fixed #785 (Enlarged doc screenshots by hover via CSS)
- Updated sphinx-bootstrap-theme to 0.2.4
- Add btn class for agenda end time tooltip
Merge pull request #786 from emanuelschuetze/1.4-fixes

Some template and doc fixes