* lwip2: better handling of ipv4_addr/t type + 3 sntp servers
* bump lwip2 version
* Only with FEATURES=1: 3 sntp servers and AutoIP enabled (169.254 when dhcp server fails)
* Only with FEATURES=1: 3 sntp servers and AutoIP enabled (169.254 when dhcp server fails)
* local CI runner: select build type
* new ipv4_addr/t definition makes things easier for IPAddress
* update local CI runner
* lwip2 changes
* lwip2: port esp-ping and espconn
* update to lwIP-2.1.0rc1: partial SACK support
fix#4176
* hash fix
* get some flash back due to mistake in conf (fragmentation & reassembly was incorrectly enabled)
(ahah I scared you)
* add missing include files
* update to lwip-2.1.0(release) + remove unused lwIP's include files
* lwIP release 2.1.0, SACK is now default, bigger, no-SACK is selectable
* fix ldscript
* pio
* rename 'sack' option to 'feat'ure option, + IP fragmentation/reassembly
* merge, fix pio
* change internal/hidden string
* pio: more lwip2 configuration: + without sack for no change in flash footprint