- SimCode.mo, BackendVariable.mo

  - for initialisation use not startvalue use pre(variable) this is the same value but it is possible to change the startvalue with the model_init.txt file 
  - also add residual equations from vars moved to known variables 
  - ToDo: 
     - change states variables fixed=true by default to fixed=false and do not set the fixed attribute from variables (dummy_states) to false if it is true. 
     - analyse the initial equaition system if additional variables must be fixed for initialisation
  - add some stuff for calculating the initialisation values via matching algorithm. This works if the number of unknown variables es equal to the number of equations for initialisation, use the debugflag=initdlowdump and uncomment the initialisation method via initial_residual function

git-svn-id: https://openmodelica.org/svn/OpenModelica/trunk@7349 f25d12d1-65f4-0310-ae8a-bbce733d8d8e

Compiler/BackendVariable.mo

@@ -321,14 +321,15 @@ algorithm
         BackendDAE.PARAM() = varKind(v);
       then
         true;
-/*  See Modelica Spec 3.2 page 88:
+/*  See Modelica Spec 3.2 page 88: 
     For constants and parameters, the attribute fixed is by default true. For other variables
     fixed is by default false. For all variables declared as constant it is an error to have "fixed = false".      
-*/    case (v) // states are by default fixed. 
+*/  case (v) // states are by default fixed. 
       equation
         BackendDAE.STATE() = varKind(v);
+        fixed = RTOpts.debugFlag("initdlowdump");
       then
-        true;
+        not fixed;
 
     case (_) then false;  /* rest defaults to false*/
   end matchcontinue;