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
Yet another fix to VariableTree copying...
Merge pull request #1739 from setowns1/bug

Yet another fix to VariableTree copying...
fixed invalidation problem with vartree input as src
updated test for vtinput as src invalidation issue
Merge pull request #1740 from naylor-b/insub_bug

bug: vtree input as src was being improperly invalidated when it had no upstream connection
Merge pull request #1738 from JustinSGray/dev

fixed a bug in cyclicworkflow
missed a test for swapped left/right sides of constraint