Achievement Bit Unsigned Int Linter

[AsherGlick]

Achievement Bit / Achievement Bit Index is an unsigned int, it represent an index into an array. Any negative value is an invalid value, we should add a way to lint for this and when we do we can add the following tests back in to check that the linter catches the errors.

<POI AchievementBit="-2147483648" Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" />
<POI AchievementBit="-5" Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" />