spatial validation rule 1221350 is to stringent

[fbergmann]

@jcschaff noticed, that libsbml is flagging compartmentmappings unitSize as wrong when it should not. lisbm complaints that:

 The attribute 'spatial:unitSize' on a <compartmentMapping> must have a value between 0 and 1, inclusive.

while the specification says:

3.6.3 The unitSize attribute
The unitSize attribute is of type double and represents the relative size of the Compartment with respect to the size of the Domains to which they are mapped. Thus for any infinitesimal subset of the Domain with size S, there exists an amount of Compartmenti of size (S*unitSizei) for i=1..N compartments mapped to that DomainType. For example, a 3D Compartment (and DomainType) which is mapped to a 3D DomainType has a unitSize which is a volume fraction of dimensionless unit. The total set of all such volume fractions mapped to a particular DomainType will typically sum to one.
If the spatialDimensions attribute of the parent Compartment is different than the spatialDimensions attribute of referenced DomainType, the unitSize attribute is a conversion factor between the two. The most common example of this would be a 2D Compartment being mapped to a 3D DomainType, such as an ER-membrane being mapped to a volumetric cell interior. In this case, the unitSize is a surface-to-volume ratio. (edited) 

so it has to be between 0 and 1 if the dimensions match, otherwise it would be a conversion factor that may well be bigger than 1.

[luciansmith]

This needs to be fixed in the spec as well.