apart from a lacking sleep_ms meta-var, it's working reliably now

Or rather: TODO: make stdin/stdout configurable so it also works for eUSCI_A1.

+= does not work for variables specified on the commandline unless
the 'override' keyword is used

reported current is inaccurate (>8% energy deviation).
Also, EnergyTrace++ significantly increases sleep/wakeup times and thus
affects the sytem's timing.