Merge pull request #887 from jikuja/fixes_for_v1.4.5

FIXED: abort launching and show error messsage if pack unzipping fails
Merge pull request #889 from jikuja/fixes_for_v1.4.5

Fixes for v1.4.5
Merge pull request #890 from jikuja/fixes_for_v1.4.5

Fixes for v1.4.5
Changed ModManager: abort pack startup if pack download fails