lwip: update to version 2.2.0 devel.#706

Open

ourairquality wants to merge 8 commits intoSuperHouse:masterfrom

ourairquality:lwip220d1

Commits on Apr 5, 2019

lwip: update to version 2.2.0 devel.
ourairquality
committed

Commits on Apr 6, 2019

Fix some networking example code that needs updating for lwip changes.
ourairquality
committed
mdns-search: add an example using the lwip mDNS service search code.
ourairquality
committed

Commits on Apr 9, 2019

README: update lwip version to 2.2.0
ourairquality
committed

Commits on Apr 12, 2019

Commits on Jun 6, 2019

lwip: update
ourairquality
committed