restored fd_step for parameters
for tests
tests pass
Merge pull request #1572 from Kenneth-T-Moore/solver

Fix for fd_step in add_parameters
Merge branch 'deriv_error_check' of github.com:naylor-b/OpenMDAO-Framework into deriv_error_check
fix for Bret
removing bad test
Merge branch 'deriv_error_check' of https://github.com/Kenneth-T-Moore/OpenMDAO-Framework into deriv_error_check