1. Add pwm support;
2. Add c++ support; Please update to the latest folder "ld".
3. Add rand in libminic;
4. Add new reset reason REASON_EXT_SYS_RST in rst_reason;
5. Update the complied script ‘gen_misc.sh(bat)’, use the new boot and remove the old one;
6. Update folder "tools", and support CRC check of bin files; Please update to the latest folder "tools".
7. Optimize the process procedure of Wi-Fi event;
8. Fix bugs in printf when its runs out of memory;
9. Fix bugs in malloc when CACHE is disabled;
10.Fix exception and WDT reset bugs when CACHE is disabled;
11.Fix some Wi-Fi connection bugs;
12.Fix some Wi-Fi scan bugs;
13.Tune API "wifi_station_get_connect_status" for more accurate WiFi positioning;
14.Porting the optimization of non-OS SDK to RTOS SDK;
15.Fix other minor bugs.
1. memory optimize;
2. add irom version libm.a: libmirom.a;
3. more apis are supported in libcirom.a, such as sscanf, sprintf, etc;
4. add c++ support in Makefile;
5. put functions to iRAM default, don't need ICACHE_FLASH_ATTR anymore;
6. remove -O2 in Makefile;
7. fix some fatal exception bugs;
8. update smartconfig to version 2.4.7;
9. update some open source files and header files;
10.use os_printf can save memory;
11.add new apis: os_random and os_get_random;
12.bug fix in lwip/net80211/wpa modules;
13.other minor changes;
1). update smartconfig to v2.2;
2). add some new APIs;
3). fix bugs in net80211 and wpa;
2. update smart_config demo;
3. fix a bug in app demo;
***internal version 0f73a14a***
