Lots of changes - most important listed below:
* modified:   src/semicontrol/gui/time_series.py
    * fixed divide by zero error on log plots
    * dynamically add plot curves when creating the parameter tree
    * fully implemented setting plot curve colors from parameter tree
* new file:   src/semicontrol/instruments/interfaces.py
    * added some abstract interfaces for instruments
* new file:   src/semicontrol/instruments/drivers/simulations.py
    * implemented some instrument simulators
* modified:   src/semicontrol/instruments/config.py
    * added some simulated test instruments