Add Greenland Iceland Ridge sections

[milenaveneziani]

This does three things:

1. it adds a arctic_sections tag to some of the existent standard_transport_sections transects;
2. it adds two important Arctic sections on the Greenland Iceland Ridge: Denmark Strait and Iceland to Faroe Islands to Scotland sections. The two transects close the budget for the Nordic Seas (together with 'Fram Strait' and 'Barents Sea Opening') and are also important for net transport calculations. Therefore, I added both tags (standard_transport_sections and arctic_sections) to these features.
3. it adds the arctic_sections transect that connects Hudson Bay with the Labrador Sea (east of Hudson Strait). This section closes the Labrador Sea budget, together with 'OSNAP section West' and 'Davis Strait'.

[milenaveneziani]

Here is an image of the sections in 2) above:

and here is one of the section in 3) (Davis Strait is also included):

[xylar]

Looks great to me!

[milenaveneziani]

Thanks @xylar.