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/Alloc.h

@@ -0,0 +1,51 @@
+/* Alloc.h -- Memory allocation functions
+2018-02-19 : Igor Pavlov : Public domain */
+
+#ifndef __COMMON_ALLOC_H
+#define __COMMON_ALLOC_H
+
+#include "7zTypes.h"
+
+EXTERN_C_BEGIN
+
+void *MyAlloc(size_t size);
+void MyFree(void *address);
+
+#ifdef _WIN32
+
+void SetLargePageSize();
+
+void *MidAlloc(size_t size);
+void MidFree(void *address);
+void *BigAlloc(size_t size);
+void BigFree(void *address);
+
+#else
+
+#define MidAlloc(size) MyAlloc(size)
+#define MidFree(address) MyFree(address)
+#define BigAlloc(size) MyAlloc(size)
+#define BigFree(address) MyFree(address)
+
+#endif
+
+extern const ISzAlloc g_Alloc;
+extern const ISzAlloc g_BigAlloc;
+extern const ISzAlloc g_MidAlloc;
+extern const ISzAlloc g_AlignedAlloc;
+
+
+typedef struct
+{
+  ISzAlloc vt;
+  ISzAllocPtr baseAlloc;
+  unsigned numAlignBits; /* ((1 << numAlignBits) >= sizeof(void *)) */
+  size_t offset;         /* (offset == (k * sizeof(void *)) && offset < (1 << numAlignBits) */
+} CAlignOffsetAlloc;
+
+void AlignOffsetAlloc_CreateVTable(CAlignOffsetAlloc *p);
+
+
+EXTERN_C_END
+
+#endif