* The mdns responder has been reworked to lower stack and memory usage. This is
a variation on the upstream code, it use malloc whereas the upstream code uses
pools. The high stack usage of the mdns responder was problem for
esp-open-rtos, so we might have to maintain the differences for now.
* Improved lwip core locking, and lock checking. Upstream improvements, that
need some added support from esp-open-rtos specific code. More core lock is
performed when calling from the esp-open-rtos code now, so a little safer. The
checking is not enforced, but projects might see warning messages and might
want to look into them.
* The esp-open-rtos lwip support has been sync'ed with the new freertos port
included with lwip. There are still some minor differences.
* A few lwip timer bugs have been resolved. This might help resolve some issues.
* Plus it picks up all the other upstream fixes and improvements.
* The default lwip stack has been lowered from 768 words to 480 words,
due to the reduced stack usage by the mdns responder.
Fix sdk_system_rtc_mem_write and sdk_system_rtc_mem_read,
the functions did not use the user-provided offsets to rtc_mem.
Without using offset, rboot's rtcdata access, and its
temp_rom handling were broken.
Add source code for functions touching the struct netif to better support lwip development: sdk_wifi_get_ip_info, sdk_wifi_set_ip_info, sdk_wifi_get_macaddr, sdk_wifi_set_macaddr.
Also code for sdk_wifi_station_get_connect_status.
Also code for wifi_get_sleep_type and set_sleep_type, noting wifi_set_sleep_type returns a bool success flag, and implement wifi_get_sleep_type using sdk_pm_get_sleep_type.
Also comment the point at which the bus clock that drives the uart changes on startup and comment out the change in the uart divisor. This at least allows a consistent uart baud rate during a restart if using the rate 115200.
* wifi_set_sleep_type returns a bool success flag.
* wifi_get_sleep_type seemed useless, just returning an argument. Added an implementation using sdk_pm_get_sleep_type.
