Virtual Timer

This example uses two tasks to demonstrates the method to use user timer supplied by RTX.

The virtual timer callback function is located in of RTX_Config.c

It is also important to set the mumber of virtual timers in use. 
This is done in the task defenition section of RTX_Config.c

Build the code and examine its operation, when the timer1 and timer2 expired, they will be 
call the callback function suppied by RTX, and act the different action according to different
timers.