Clarification on the versioning of the EUNIS habitat classification 2007 2012 2019.

The habitat descriptions of the EUNIS classification 2007 were revised in 2012. 
The 2007 habitat types were not changed. In the 2012, the description revision mostly 
replaced Palaearctic or UK Marine habitat classification codes used in habitat descriptions 
at levels 5 and below with their EUNIS classification equivalents. In 2019, the classification
was further amended to include two new habitats of the revised Resolution 4 of Bern Convention 
as adopted at the 38th Standing Committee meeting, November 2018. The two habitat types are 
G3.4G Pinus sylvestris forest on chalk in the steppe zone and X36 Depressions (pody) of the Steppe zone.