removed ref to specific Vol

we have a new volume to contend with in WMO No. 306 (Vol I.3) …
registers from there are also included herein so I removed the
reference to Vol I.2
removed further references to Vol I.2
'quantity kind' not 'quantities' and 'Vol I.3' too
change type definitions

the Quantity Kinds are type ‘qudt:QuantityKind’ … and also, I think
that we can make them skos:Concept too (based on Simon’s work
(http://environment.data.gov.au/def/op). They are not owl:Class nor
subClassOf skos:Concept.
additional type definition

modified to include the sub-types of qudt:QuantityKind where known (as
specified in common/c-15)