Concept check for basic points predicates

Some don't match the concept because of strange
assignment operator problem
editing concepts
edits
merging
Merge remote-tracking branch 'david/minorDoxyConcepts' into improveThresholdPredicate

Conflicts:
	src/DGtal/kernel/BasicPointPredicates.h
	src/DGtal/kernel/BasicPointPredicates.ih
tested CPointPredicates on BasicPointPredicates
indent
Merge branch 'master' into improveThresholdPredicate
warning fix
more warning fix
Merge pull request #726 from elcerdo/improveThresholdPredicate

CPointPredicate enforcement