Gns3-gui

* Fix error in HTTPConnection.request for Python3.6. Fixes 2793
* Catch more OSError/PermissionError when checking md5 on remote images. Fixes 2582
* Fix exception when grid size is 0. Fixes 2790
* Catch PermissionError when scanning local image directories. Fixes 2791
* Revert "Make sure the latest PyQt5 version 5.12.x is used on Windows." Ref 2778

* No changes.

* Do not make NPF or NPCAP service mandatory to start the local server on Windows.
* Fix OverflowError error with progress dialog. Fixes 2767
* More fixes for stuck progress window. Fixes 2765
* Fix adding multiple devices - stuck progress window. Fixes 2765
* Make sure the latest PyQt5 version 5.12.x is used on Windows.
* Show a warning when a config export is not supported. Ref 2762

* No changes on the GUI.

* Better description to why an appliance cannot be installed.

* Disable computer hibernation detection mechanism. Ref 2678
* Add some advice for request timeout message. Fixes 2652
* Show/Hide interface labels when status points are not shown. Fixes 2690
* Do not print critical message twice on stderr. Replace QMessageBox calls with no parent by log.error()/log.warning().
* Show critical messages before the main window runs.
* Avoid using PyQt5.Qt, which imports unneeded stuff. Fixes 2592
* Fix SIP import error with recent PyQt versions. Fixes 2709
* Upgrade to Qt 5.12. Fixes 2636
* Adjust the setup wizard (VMware image size, layouts).