Input functions

An input tab is added along with the other parts tabs. This new input tab contains input functions such as Impulse function, Step function, and Wave function, all of which can be used to set forcing functions on one or more molecules.

The CatalogWidget widget which originally just showed the nodes and connections now contains a new slot called addNewButton that allows other plugins to add new tabs to the Catalog. The SimulationEventTool plugin uses this feature to add the inputs tab. The ModuleTool uses this feature to add the Module tab.