bugfix: expand all sub-trees
bugfix: expand all sub-trees

The initial RT ticket was #373851, and was supposed to be fixed by the #5,
but it appears that the fix was only partial (RT #428238)
The "collapse" field was only updated in the ZMenu, but not in the URL

Ensembl/ensembl-webcode,Ensembl/ensembl-webcode,Ensembl/ensembl-webcode,Ensembl/ensembl-webcode,Ensembl/ensembl-webcode