Add some abstract methods to Laurent polynomials base class

[jdemeyer]

Rename LaurentPolynomial_generic to LaurentPolynomial (it's not a "generic" implementation, it's an abstract base class) and put some abstract methods there, like cpdef _add_.

CC: @roed314

Component: basic arithmetic

Author: Jeroen Demeyer

Branch/Commit: b0cee8a

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/23606

[jdemeyer]

Branch: u/jdemeyer/add_some_abstract_methods_to_laurent_polynomials_base_class

[jdemeyer]

Commit: b0cee8a

[jdemeyer]

New commits:

b0cee8a

Add some abstract methods to Laurent polynomials base class

[tscrim]

comment:3

Should we worry about old pickles? Specifically, should we add a register_unpickle_override?

[jdemeyer]

comment:4

Replying to @tscrim:

Should we worry about old pickles?

I don't think so because

1. There shouldn't exist objects of type LaurentPolynomial_generic in the first place, only of subclasses.

2. It's a Cython class so pickling probably won't work anyway.

[tscrim]

Reviewer: Travis Scrimshaw

[tscrim]

comment:5

Alright. Positive review.

[vbraun]

Changed branch from u/jdemeyer/add_some_abstract_methods_to_laurent_polynomials_base_class to b0cee8a