Control timing of loops and sensor polling

Right now there is not any timing regulations on the polling of the sensors. Fix this so the sensors are called at regular and appropriate rates (check the data sheets when in doubt). This timing should be regulated by a hardware timer. The calls should also be based on frequencies and times of last call, not relative frequencies and counters (if something is 100 Hz and another 1 Hz, don't just call the latter 1 out of every 100 times the first is called, use a timer)