Fix base module digging.
account for psi skills when promoting soldiers.
fix soldiers not spawning at alien bases.

refactored the code to find a valid spawn point to it's own function and
called it when setting up xcom units in alien bases, and when placing civilians

fixes the following:

units not showing up when taking 26 soldiers to an alien base in an avenger.
too few civilians showing up at terror sites.
0 civilians should also exist as a possibility.
initial FOV wasn't being calculated in base defense/assault missions.
update portuguese translation.
update the update for the portuguese translation.
fix for mind control/cydonia transition issue.
set default explosion height to 0.