[REVERT] Revert part of 648ccc7
[FOLD] Rewrite STObject::setType for improved performance
[FOLD] Avoid a mutex 99+% of the time in SField::getField
[WIP] Begin work on removal of mTNByID:
 * Changes the rest of the code needs to work with
 * Remove mTNByID, dirty tracking
[FOLD]