Spawn System fixes

See merge request !46

if a map is not configured in desolation/config.cpp (or any override) the variable DS_var_SpawnSetting is not set thus cannot be read in on region selected. This fixes it by adding a check and spawning randomly if the var does not exist since witouht any configuration spawning randomly is the only option anyway.

to prevent forgetting this in any script execution branch when refactoring any spawn code

when spawn choosing is disabled and the user forgets to add markers a script error triggers spawning the player at [0,0,0] and not finishing initialization