1. Add IIC slave mode RX by interrupt function (Now, master mode TX/RX and slave mode RX functions are done)
2. Add Timer1 configuration in timer driver
3. Modify the ACMP default initialization setting 
4. Add on/off switch for debug code to reduce size

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1353 bbd45198-f89e-11dd-88c7-29a3b14d5316