add _unevaluated_Mul to mul.py and modify _unevaluated_Add
align code and inline comments
use minpoly as fallback for radsimp; watch for Numbers

- also work with normal form of equation
remove minpoly use from radsimp

This is untraversed code at present and I'm not sure that there
are expressions that will make it to this point that will produce
a minimal polynomial that can be solve.
ok
rework recursion and handle powers according to assumptions