Add vary_weights to convert_input.py and correct fci conversion.
Add vary_weights to convert_input.py and correct fci conversion.

The lanczos table was accidentally being printed out (with sparse=false)
when an fci (diagonalisation/lapack) calculation was specified.

hande-qmc/hande,hande-qmc/hande,hande-qmc/hande,hande-qmc/hande,hande-qmc/hande,ruthfranklin/hande