Lattice tutorial

Begin to write tutorial for lattice class

Add getDoubleArrowTable in lattice.java (+ iuml + test)
Rename getArrowRelation in lattice.java

Update ChangeLog
Add isCN method in Lattice.java

Implements the recognition algorithm from "Doubling convex sets ..." paper
Add test, update iuml file and ChangeLog
Merge pull request #72 from JeanFrancoisViaud/master

Lattice tutorial