stimuli.txt moved to data_input.txt
new verification data files key_input.txt & data_output.txt
dependency files now moved into 2 variables SRC_FILES & SIM_FILES
testbench enhancement

* now 2 files with stimuli data: data_input.txt & key_input.txt
* new file with the expetcted data output: data_output.txt
* new test: Inverse permutation known answer test