Opening files is slow on some internet connections

[wifi-left]

In China, opening .dat files with the newest plugin is very slow But in the version 0.6.8, it was very fast I found that if I didn't have access to raw.githubusercontent.com, the file would be hard to open, or impossible to open

[reserveword]

suggestions for implementation: disable rendering feature when texture loading failed, or simply use default(transparent or purple-black) texture as default.