Wrong space group detection

The issue appears when Hall and HM are the same (in this case A 2), from the space-group.txt:

5
A 2y
A 2,A 1 2 1
x,y,z
-x,y,-z
x,1/2+y,1/2+z
-x,1/2+y,1/2-z

And:

5
A 2
A 1 1 2
x,y,z
-x,-y,z
x,1/2+y,1/2+z
-x,1/2-y,1/2+z

Since, space groups are kept in:
map<string, const SpaceGroup*> sgbn;

And keys for this map (which are unique) are either Hall or HM space group title, one of the above definition is being overwritten.

We could try to move to:

map<string, map<string, const SpaceGroup*> > sgbn;
sgbn["Hall_name"]["HM_name"] = spg;

Start with space-group.txt and trace where the sgbn map is populated and queried. Reproduce the collision between the A 2y/A 2 definitions, then verify that both Hall and HM names remain addressable without one definition overwriting the other.