LWIP RTEMS Readme

Ported by: Rolf Schroeder <Rolf.Schroedter@dlr.de>
           Karl Scheibelhofer 
Date:      17 August 2005

We did not touch the LWIP sources.
LWIP has a general OS interface "sys_arch.c" including
- starting a thread
- semaphore actions (create, obtain, release)
- mailbox actions (message queue)

The only point left open is, that for some reason lwip tasks need a
RTEMS_TIMESLICE to run properly.

Rolf would really like some feedback.