introduce epilogue block

src/CodeInterpreter.hh

src/ComputingTasks.hh

src/DynareBison.yy

src/DynareFlex.ll

src/ExprNode.cc

src/ExprNode.hh

src/Makefile.am

src/ModFile.cc

src/ModFile.hh

src/ModelEquationBlock.cc

src/ModelEquationBlock.hh

src/ParsingDriver.cc

src/ParsingDriver.hh