fixed g++ warnings

git-svn-id: svn://svn.code.sf.net/p/quantlib/code/trunk/QuantLib@18484 8618b1d8-e22c-0410-b026-96a5dba3e089
ensure backward compatibility of ublas extension

git-svn-id: svn://svn.code.sf.net/p/quantlib/code/trunk/QuantLib@18485 8618b1d8-e22c-0410-b026-96a5dba3e089
fixed g++ warnings (thanks to Peter Caspers)

git-svn-id: svn://svn.code.sf.net/p/quantlib/code/trunk/QuantLib@18486 8618b1d8-e22c-0410-b026-96a5dba3e089
Prevent out-of-bound access to degenerate schedule.

git-svn-id: svn://svn.code.sf.net/p/quantlib/code/trunk/QuantLib@18487 8618b1d8-e22c-0410-b026-96a5dba3e089