Refactorisation of families

[nthiery]

Log of the attached patch:

• Families are parents, in the (Finite/Infinite)EnumeratedSets category
• New class EnumeratedFamily; Family accept any (Finite)EnumeratedSet as input
• Improves the output of lazy families, and update accordingly the
  doctests in CombinatorialFreeModule, ...
• Clean trailing whitespaces
• Use TestSuite
• Fix enumeration for FiniteFamily

Depends on #5891

CC: @sagetrac-sage-combinat

Component: combinatorics

Keywords: Family, enumerated set

Author: Florent Hivert

Reviewer: Nicolas M. Thiéry

Merged: sage-4.3.alpha0

Issue created by migration from https://trac.sagemath.org/ticket/7208

[nthiery]

Description changed:

--- 
+++ 
@@ -1,8 +1,10 @@
 Log of the attached patch:
 
-- Families are parents, in the (Finite/Infinite)EnumeratedSets category
-- New class EnumeratedFamily; Family accept any (Finite)EnumeratedSet as input
-- Improves the output of lazy families, and update accordingly the
+* Families are parents, in the (Finite/Infinite)EnumeratedSets category
+* New class EnumeratedFamily; Family accept any (Finite)EnumeratedSet as input
+* Improves the output of lazy families, and update accordingly the
   doctests in CombinatorialFreeModule, ...
-- Clean trailing whitespaces
-- Use TestSuite
+* Clean trailing whitespaces
+* Use TestSuite
+
+Depends on #5891

[nthiery]

comment:4

We should use the occasion to fix this bug:

sage: f = Family(["c", "a", "b"], lambda x: x+x)
sage: list(f)
['aa', 'cc', 'bb']

[nthiery]

comment:5

The updated patch is supposed to fix it. Florent: please review!