add otPlatRadioGetCaps method to check radio capabilities (#53)

add doxygen for otRadioCaps

remove tmp file

include/platform/radio.h

@@ -77,6 +77,17 @@ enum
     kPhyUsPerSymbol     = ((kPhyBitsPerOctet / kPhySymbolsPerOctet) * 1000000) / kPhyBitRate,
 };
 
+/**
+ *   This enum represents radio capabilities.
+ *
+ */
+
+typedef enum otRadioCaps
+{
+    kRadioCapsNone          = 0,  ///< None
+    kRadioCapsAckTimeout    = 1,  ///< Radio supports AckTime event
+} otRadioCaps;
+
 /**
  * This structure represents an IEEE 802.15.4 radio frame.
  */
@@ -272,6 +283,13 @@ ThreadError otPlatRadioHandleTransmitDone(bool *aFramePending);
  */
 int8_t otPlatRadioGetNoiseFloor(void);
 
+/**
+ * Get the radio capabilities.
+ *
+ * @returns The radio capability bit vector. The stack enables or disables some functions based on this value.
+ */
+otRadioCaps otPlatRadioGetCaps(void);
+
 /**
  * @}
  *