fix and test GitHub issue 15

git-svn-id: svn://svn.code.sf.net/p/rdkit/code/trunk@2464 a5045d30-4826-4484-9c7f-6e55a06ddc77
switching to an SSS fp size of 2048; this helps a lot with ChEMBL queries

git-svn-id: svn://svn.code.sf.net/p/rdkit/code/trunk@2465 a5045d30-4826-4484-9c7f-6e55a06ddc77