Slider changes

[barnums]

Minor changes to sliders: parameter textbox now editable and drop-down menus now open by default

[barnums]

Also removes initial conditions from inference/sliders if all states of the form *.drug, sets ICs to zero as default. If at least one state is not of this form, then all state ICs treated are treated as parameters as before. Tests reconfigured to reflect these changes. Usual inference tests still causing problems.