Adds dependency org.openscience.cdk.signature
Make Hansen Ames and U251 show as installed

For this they need to be marked as groups
Also copied a description from the help texts
Adds qualifier n.b.ds.m.r.ames and n.b.ds.m.r.u251
Install R when insalling net.bioclipse.r.ames model
Add dependency to r and qsar feature from u251 model
Removed smartcyp from dsmodels site
Release 2.6.1

Merge branch 'develop'