* use system with @args so that we can query the return value
* code style improved for readability
* diff shows the filtered difference
* ok instead of cmp_ok to show not the whole content of vars
Often in the past travis was hitting a limit (50min?).
This is a try to make reasonable cuts to the unit tests:
- For STARTTLS some checks with OPenSSL are skipped
- For JSON and HTML outputs --ids-friendly was added assumming we
don't change the output of ticketbleed, CCSI, HeartBleed and ROBOT any more.
- There's also not point to run those checks against badssl
- for the diff check we switch to 'or diag' to display a dfifference
