[BUG][INSTALLER] Installer appears crashed while downloading / extracting

[namida]

Except for the occasional update of the "X of Y downloaded" (or "extracted") text, there's no indication that the installer is doing anything while downloading, and it appears as if it's crashed.

One user has claimed the installer crashes when he tries to use it; as he was able to see the list of level packs, this suggests the crash comes only when the download was actually started. This means there's a good chance it hadn't actually crashed, but it was just this issue.

Workaround: None needed. The installer is working, it just doesn't respond properly to user input / system messages while downloading. But this needs to be fixed for user-friendliness reasons.

[namida]

I've uploaded an improved installer that shows a clearer indication that it's making progress. Leaving this open as there's still room to improve it further.

[kokopelli]

Hi!
We've just downloaded the V12.10.3 installer and tried to install in a complete new folder. After selecting all level packs the installer reported an error while extracting SEBLems. I've made a screenshot.
Kokopelli