Notes:
- header has version 2.2.0.
- This sync did not bring in ./test directory, though we should.
- New NetworkInterfaces are introduced by this merge.
- Keil compiler support.
- FreeRTOS_IP.h new API xApplicationGetRandomNumber().
- FreeRTOS_IP_Private.h new eIPEvent_t eNetworkTxEvent.
- FreeRTOS_Stream_Buffer.h removing static xStreamBufferIsEmpty() and xStreamBufferIsFull().
- FreeRTOSConfigDefaults.h provides default ipconfigDNS_RECEIVE_BLOCK_TIME_TICKS.
- other type changes.