GitLab

- Add placeholder images (use the human equivalent)
- implement Does_Self_Repair
- gameSettings allows to select if neutral alien units are present at beginning
- place randomly some alien factories with unit around at game start.
- hide alien units from hangars (selection)
- fix steal of neutral units.

- Remove unused methods.

- Clean-up (space, pass by reference instead of by smart pointer).

- Formmatting
- use some reference instead of pointer.
- Factorize some code.

Replace clanlogo1.pcx

See merge request !18

Use `std::recursive_mutex` instead `std::mutex`. (useful at least for `cConnectionManager::openServer`).

split LoadLanguage().