BREAKING: Moved io.exit from hop_runner to runHop command

A bit easier to test, right?
task_result_tests: cleanup
testing help output
TaskArgument: allow numbers, as long as they are not the first char
testing some help output
extended args work

progress on Issue #40
HopConfig rework
Runner: more renaming
Using extendedArgs in tasks
rename util to shared
tweaks to shared
TaskArgument uses the same validation logic as Task names
TaskContext is much more simple -> owned by Task
One less parameter to Task.run