improved boundary conditions for the Fokker-Planck equations

git-svn-id: svn://svn.code.sf.net/p/quantlib/code/trunk/QuantLib@18488 8618b1d8-e22c-0410-b026-96a5dba3e089
updated vc10 project files

git-svn-id: svn://svn.code.sf.net/p/quantlib/code/trunk/QuantLib@18489 8618b1d8-e22c-0410-b026-96a5dba3e089
fixed multi dimensional definition of square root Fokker-Planck operator

git-svn-id: svn://svn.code.sf.net/p/quantlib/code/trunk/QuantLib@18490 8618b1d8-e22c-0410-b026-96a5dba3e089