prepare for a command-line interface for specrunner
improve Group test specs
Improve Example test specs
Tidy up creation of Result objects
wierd name-visibility issue:
    new specRunner.Whatever(...)
is OK, but
    Whatever = specrunner.Whatever
    new Whatever(...)
says that Whtever is undefined.
bin/specrunner kind of works
get VCD-file import and plotting working in this environment
add class Observation, can generate a verilog wrapper, run iverilog+vvp and produce vcd file.
Observation now automatically imports the vcd data to the database