Fixed debugging Units

Removed ensuring there is a target in getTarget(), which solves a crash when debugging in PyCharm. *Previously if an Unit was opened during debugging it would crash if the unit had no target, failing the assertion. *If there is no current target getTarget() will instead return itself (this functionality was already implemented and probably how it handled it before adding this assertion)

*I have done some basic tests and now Unit can be opened BUT in some cases it crashes upon inspecting a target of a unit. However this alteration is still better as it does just SOMETIMES crash instead of ALWAYS

src/Unit.cpp

@@ -328,7 +328,6 @@ void Unit::ability(sc2::AbilityID ability, const Unit& target) const
 Unit Unit::getTarget() const
 {
     BOT_ASSERT(isValid(), "Unit is not valid");
-    BOT_ASSERT(hasTarget(), "Unit has no target");
 
     // if unit has order, check tag of target of first order
     if(getUnitPtr()->orders.size() > 0){