Fix dropping of items and digging after letting go from scale/hangle

[fritzw]

Fixes #119.

Dropping items when letting go from scaling was just the missing break.

The hangle case is a bit more complicated because the drop command is initiated by checking LastComDownDouble, which is set based on LastCom. So by clearing LastCom when letting go, the problem goes away. Dropping items after landing as before is still possible by pressing Down-Down-Throw again while in the air instead of just Down-Throw as before.

I'm not sure if the if in line 3548 is really necessary, because ObjectComLetGo can only return false for an object which can scale/hangle but has no "Jump" action, so it can not let go. At that point, we can as well leave LastCom alone, I guess, maybe the object wants to do something special with it...

Weapons were not tested, and I'm unsure if there are any weird interactions with scripts or other custom content.

[fritzw]

Maybe a static function with three arguments for cObj, xdir, pPlayer would be more performant than a lambda. On the other hand, both the lambda and the static function are probably inlined by the compiler anyway, since the lambda does not leave the scope, so meh...