Avoid choking/delays when connected to several clients

See merge request !1

* In ServerCheck polling loop for new msgs, turn a continue; into a break;
* Add wordy explanation for this change

Explanation for break in ServerCheck loop

fix bug where the first signal sending is skipped, make histogram being printed when a reset is done, syntax cleaning

Fix bug in signalsubscriptions being skipped when not perfectly aligned, limit number of packets/s being dispatched, make log messages more uniform, throttle flash memory in all possible ways to avoid skipping, make control loop use nominal execution time to compare against message timestamps to avoid jitter

update master to include documentation, licencing, and installation instructions for Debian 8.2 based beaglebone images

fix incorrect addition of mass_bias on deflation, use absolute pressures everywhere, comment out debugging prints

removes psi model, adds documentation of the massflow controller interface, removes unnecessary calibration mode code