Compiler: modify cpp codegen for array and functions.
Compiler: modify cpp codegen for array and functions.

For arrays literals we now use the makeArray() helper instead of the
constructor, this avoids specifying the type of the array at that point.

For functions, we now use a std::function<...> type instead of auto. This
makes it easier to specify the type of newtonSolveSystem() in the back-end.

sintefmath/equelle,sintefmath/equelle,atgeirr/equelle,atgeirr/equelle,babrodtk/equelle,atgeirr/equelle,babrodtk/equelle,babrodtk/equelle,atgeirr/equelle,sintefmath/equelle,atgeirr/equelle,sintefmath/equelle,sintefmath/equelle,atgeirr/equelle,atgeirr/equelle,babrodtk/equelle,babrodtk/equelle,babrodtk/equelle,sintefmath/equelle,sintefmath/equelle,babrodtk/equelle,sintefmath/equelle,atgeirr/equelle