A few issues when no network filename is given

[isty2e]

Other than local engines, I sometimes connect to engines on cloud instances via ssh, with commands stored in script files. In that case, the network file name is missing since the command in config.txt is something like ../gtp_katago.sh, and this causes two problems:

1. In menu-engines, since the names of engines are automatically fixed to the network file name, it is hard to distinguish between them. Supporting aliases for engines will resolve this problem.
2. Settings pane won't open.

[kaorahi]

#787 may solve 1. I cannot reproduce 2.