trunk preprocessor: some cleanups related to sparse mode (removed...

trunk preprocessor: some cleanups related to sparse mode (removed SimulSparseStatement class and incorporated it into SimulStatement, determine mode at preprocessing time instead of runtime in StochSimulStatement)


git-svn-id: https://www.dynare.org/svn/dynare/trunk@2595 ac1d8469-bf42-47a9-8791-bf33cf982152