* add gn stuff for ios

* restyled

* rebase, use target_default config for cflags, cxxflags, defines, ldflags instead of getenv()

* chugga

* sheesh

* restyled

* re-restyled

* fixup where we expect to find encoder.h

* restyle

* move app stuff around more

* restyle

* use <app/chip-zcl...> everywhere

* restyle