Reduced base hero threat to 2. This should go in line with the default found in most HeroData files which will eventually determine this value instead.
Renamed GetThreatOfEnemy of GetThreat since it can also be used on allies.
Changed GetThreat so that any unitSelf function calls are done outside the function so they aren't called several times.
Changed GetThreat so it also works on allies and ignored some checks when it is used on unitSelf. These checks would return the same value every time anyway.
Now reducing the RetreatFromThreat Utility value by the threat value of allied heroes in range. This makes it so the hero knows when the ally nearby is useful (e.g. a ganker/carry) or not (e.g. another support).