#139 xTimerChangePeriod documentation unclear on starting timer

[Christopher Head]

The xTimerChangePeriod function’s documentation mentions that it can be called on both active or dormant timers. What it does not say is that, if called on a dormant timer, it also starts the timer! Actually this is mentioned, but only in a small comment in the example code section, not in the description of the function’s behaviour where I would expect it.