add filtering support of infeasible(None) objective value
add constraint filtering support of paretofilter and add constrained example of single_objective ei with constraint
minor error modifications
Merge remote-tracking branch 'origin/dev' into dev
Merge remote-tracking branch 'origin/dev' into dev
Merge remote-tracking branch 'origin/dev' into dev
test works
Merge pull request #1721 from cwmine/dev

add constraint filtering support for paretofilter and modified constrained  single_objective_ei to test it