Code cleanup, inherit JK, D and T from RS and a bugfix for the logic element

Code cleanup, inherit JK, D and T from RS and a bugfix for the logic element

- reuse code
- undeclared inputs default to false where applicable
- remove unused tInput
- JK, D and T FF now inherit from RS with dominant R input, so they all
have a R and a S input to preset the output
- fix the nonfunctional <inverted> element of the logic element