lwipopts.h: Enable the new TCP_EXTEND_ROM_PBUFS feature.
lwipopts.h: Enable the new TCP_EXTEND_ROM_PBUFS feature.

With this, TCP sending should finally be reliable without risk of running out of memory.

ambrop72/aprinter,johnkingsley/aprinter,johnkingsley/aprinter,johnkingsley/aprinter,ambrop72/aprinter,ambrop72/aprinter,johnkingsley/aprinter,ambrop72/aprinter,johnkingsley/aprinter,ambrop72/aprinter,ambrop72/aprinter,ambrop72/aprinter,johnkingsley/aprinter,johnkingsley/aprinter