fix for warning
Merge pull request #1627 from Kenneth-T-Moore/dev

Fix for a warning about complex casting
Merge branch 'vtree_boundary' of github.com:naylor-b/OpenMDAO-Framework into vtree_boundary
Fixed my bug
fix on test
cache added
added deriv_ignore metadata
Merge branch 'vtree_boundary' of https://github.com/Kenneth-T-Moore/OpenMDAO-Framework into vtree_boundary
change
Merge branch 'vtree_boundary' of github.com:naylor-b/OpenMDAO-Framework into vtree_boundary
Merge branch 'dev' of https://github.com/OpenMDAO/OpenMDAO-Framework into vartree_asmb_boundary
Merge branch 'vtree_boundary' of https://github.com/Kenneth-T-Moore/OpenMDAO-Framework into vartree_asmb_boundary
change
Merge branch 'vtree_boundary' of https://github.com/Kenneth-T-Moore/OpenMDAO-Framework into vartree_asmb_boundary
change
Merge branch 'vtree_boundary' of https://github.com/Kenneth-T-Moore/OpenMDAO-Framework into vartree_asmb_boundary
change
change
Merge branch 'vtree_boundary' of https://github.com/Kenneth-T-Moore/OpenMDAO-Framework into vartree_asmb_boundary
more bug fixes