7.8.2

1. Fix - hidden canvas in Jupyter Lab, https://root-forum.cern.ch/t/63097/
2. Fix - repair small bug in TF3 painting

Also bug-fixes from version 7.7.6

1. Fix - latex super-script without leading symbol, https://root-forum.cern.ch/t/63114/
2. Fix - correctly read std::pair<> without dictionary, https://root-forum.cern.ch/t/63114/
3. Fix - chromium in mobile device emulation mode, https://root-forum.cern.ch/t/63201/
4. Fix - files remap for root.cern site using fallback URL