add ota algorithm for device

1. effective "Differential Upgrade" patch algorithm with high compression rate
2. effective recovery algorithm support recovery firmware in blocks which has low memory consumption and wear-leveling strategies, especially suitable for embeded devices with low RAM.
3. add sample ota bootloader project, see:
board\TencentOS_tiny_EVB_MX_Plus\KEIL\ota\ota_bootloader_recovery
4. add sample application project for download firmware through http, see:
board\TencentOS_tiny_EVB_MX_Plus\KEIL\ota\ota_application_download_through_http
5. add sample application project for download firmware through qcloud explorer console, see:
board\TencentOS_tiny_EVB_MX_Plus\KEIL\ota\ota_application_download_through_qcloud_iot_explorer
6. an OTA markdown document is pending

components/ota/common/lzma/3rdparty/7zCrc.h

@@ -0,0 +1,25 @@
+/* 7zCrc.h -- CRC32 calculation
+2013-01-18 : Igor Pavlov : Public domain */
+
+#ifndef __7Z_CRC_H
+#define __7Z_CRC_H
+
+#include "7zTypes.h"
+
+EXTERN_C_BEGIN
+
+extern UInt32 g_CrcTable[];
+
+/* Call CrcGenerateTable one time before other CRC functions */
+void MY_FAST_CALL CrcGenerateTable(void);
+
+#define CRC_INIT_VAL 0xFFFFFFFF
+#define CRC_GET_DIGEST(crc) ((crc) ^ CRC_INIT_VAL)
+#define CRC_UPDATE_BYTE(crc, b) (g_CrcTable[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
+
+UInt32 MY_FAST_CALL CrcUpdate(UInt32 crc, const void *data, size_t size);
+UInt32 MY_FAST_CALL CrcCalc(const void *data, size_t size);
+
+EXTERN_C_END
+
+#endif