Spit out ACADO symbolics from CasADi expressions for debugging purposes

[mvukov]

For the debugging purposes within HIGHWIND project, we must to check whether or not CasADi generated code makes memory related issues, e.g. cache misses. In that sense, we should not use CasADi generated C-code, but use the path: CasADi expressions (python) -> ACADO expressions (c++) -> ACADO generated C-code.

[ghorn]

You got it