Add begin() and end() to Statistic.
Add histogram class and test.
Add CBinner concept.
Fix doc, concepts. Minor code fixes.
Merge branch 'master' of github.com:DGtal-team/DGtal into ImproveStatistic
Add math concepts.
Update boost.dox.
Update ChangeLog.
Minor fixes.
Merge pull request #699 from JacquesOlivierLachaud/ImproveStatistic

Improve statistic. Self merging.