Fixes for ticket #57

preprocessor:
* add a field "M_.orig_endo_nbr" containing the nbr of endogenous before adding aux vars
* always provide "M_.aux_vars" (define it to "[]" when there is no aux var)
* rename "M_.aux_vars().orig_endo_index" to "M_.aux_vars().orig_index"

M-files:
* for commands which accept a list of variables (stoch_simul, osr, estimation, dynasave, dynatype, datatomfile), when no variable is given, use only the set of original endogenous (without aux vars) as the default
* when displaying the decision rule, when there is aux vars in the state variables, replace them by their original name (with the right lag)
* in "steady", don't display aux vars
* special exception for ramsey policy: all vars (including aux vars) are displayed, because the system of aux vars from ramsey policy is not compatible with the aux vars from the preprocessor


git-svn-id: https://www.dynare.org/svn/dynare/trunk@3166 ac1d8469-bf42-47a9-8791-bf33cf982152