rename layered fingerprint2 -> pattern fingerprint
rearrange fingerprint code a bit

git-svn-id: svn://svn.code.sf.net/p/rdkit/code/trunk@2460 a5045d30-4826-4484-9c7f-6e55a06ddc77
use pattern fingerprint
switch rdkit fp to only go to length 6

git-svn-id: svn://svn.code.sf.net/p/rdkit/code/trunk@2461 a5045d30-4826-4484-9c7f-6e55a06ddc77