Code duplication

Remove duplicate code!

operators.hpp and state_operators.hpp have a lot of things in common,

• BaseStateOperator<double> and BaseOperator are exactly the same. Retain the templated version.

• Rt_Operator, R_operator, Effort and G_Operator classes are unused after the templated versions were included.

• Remove moot input_vec class used only in single_pipe demo.

• utils.hpp has two diagonalBlock functions, one for BaseOperator and another for BaseStateOperator. After the above is done, they can be united.