fixed includes and timex initialization in ping lib
only cosmetics
started adding at86rf231 driver

at86rf231 TX and RX

driver is using vtimer instead of hwtimer_ functions, TO CHECK

vtimer debug function prototype fix
added AT86RF231 payload size
fixed some ifdefs and added necessary includes to transceiver.h
started adding at86rf231 driver

at86rf231 TX and RX

driver is using vtimer instead of hwtimer_ functions, TO CHECK

vtimer debug function prototype fix
added AT86RF231 payload size
bugfixes : #endif was missing, and TRANSCEIVER_AT86RF231 was colliding with another transceiver.
fixed some ifdefs and added necessary includes to transceiver.h