Milestone A rewrite using CLOS

When the package was conceived, CLOS was not an option. Currently, it appears that CLOS is solid enough to be used throughout the project.

Specific objectives

There are several versions of the Grobner basis algorithm. They use slightly different representation of polynomials and polynomial ideas. Inheritance can be used to have a cleaner design, by using a number of generic functions, such as:

• polynomial arithmetic
• division and normal form

Moreover, "sugar" can be handled in an aspect-oriented style, as manipulating sugar is naturally an :after method for several generic functions. Handling "sugar" in this manner should eliminate code duplication.