Add getDoubleCircArrowTable, isAtomistic, isCoAtomistic

Try getDoubleCircArrowTable on a CN lattice (examples are in isCN test).
It's not as easy as I thought but it's much more interesting !
Correct style
Modify tutorial generation & Move Arrows method
Move/Improve code for arrows methods

Correct minor points in tutorial generation
Update ChangeLog
Merge pull request #102 from JeanFrancoisViaud/master

Add getDoubleCircArrowTable, isAtomistic, isCoAtomistic