Temp disable of symbol store to make forward progress

More Qt 5.12.6 fixes

Build using downloaded Qt

Fix

Download and install Qt

Use Win 10 SDK

More

Still fighting

Fighing with appveyor

Trying to find vcvars

Fighting with vcvars location

Move to VS 2017, 64 bit

Switch to 1.14.4 gstreamer

Relative path to pdb

Fix tagged release builds. PDB artifacts

Switch to Stable 3.5

More fixes for symbol storage

Store symbol artifacts only for Stable builds

Only specify 5.11 so minor version will float to whatever is on AppVeyor