added contributors in README

add experiment files for RV2021

Release v0.4 (#15)

* Fixed and clarified the signal interpolation in SimulinkSUL
    * For inputSignal = a1, a2, ..., an, we construct a timed word w = (a1, 0), (a2, T), (a3, 2 * T), ... (an, (n - 1) * T) and execute the Simulink model by feeding the piecewise-linear interpolation of w, where T is the signal step.
* Report the concrete counterexamples with timestamps for clarity

made S3 larger

do not remove TimeoutEQOracle in CI

S1 and S4 sample inputs