Implementation of Littelmann path model for crystals

[anneschilling]

This patch implements the crystal graph using the Littelmann path model.
The elements are LS paths generated from the straight-line path to a given weight.
Also, the iterator function and lists in crystals is cleaned up.

CC: @sagetrac-sage-combinat

Component: combinatorics

Keywords: crystals, sd40

Author: Mark Shimozono, Anne Schilling

Reviewer: Anne Schilling, Mark Shimozono

Merged: sage-5.3.beta1

Issue created by migration from https://trac.sagemath.org/ticket/12251

[anneschilling]

Reviewer: Anne Schilling, Mark Shimozono

[anneschilling]

Description changed:

--- 
+++ 
@@ -1 +1,4 @@
-Crystal graph of LS paths generated from the straight-line path to a weight.
+This patch implements the crystal graph	using the Littelmann path model.
+The elements are LS paths generated from the straight-line path to a given weight.
+
+

[anneschilling]

comment:2

Hi Mark,

The latest version of the patch is attached and ready for the final review (it is also on the sage-combinat queue).

Anne

[anneschilling]

Description changed:

--- 
+++ 
@@ -1,4 +1,5 @@
-This patch implements the crystal graph	using the Littelmann path model.
+This patch implements the crystal graph using the Littelmann path model.
 The elements are LS paths generated from the straight-line path to a given weight.
+Also, the iterator function and lists in crystals is cleaned up.
 
 

[anneschilling]

Changed keywords from crystals to crystals, sd40