Deprecated. Don't use for new development and try to migrate existing uses.
This function answers the question whether a given string is a formally valid organisation number.
Note that all valid social security numbers are also valid organisation numbers. This is because companies of type "enskild firma" uses the owners social security number as organisation number.
The special case of a null-string will give a return value of 0.
Returns 1 if the organisation number is formally valid and 0 otherwise.