Fixed prefix for rtems.cfg. Standard rtems prefix is /opt/rtems<version> and not /opt/rtems-<version>, which would break GNU triplets.
Adds basic README for compiling the gw, fixed rtems.cfg. rtems.cfg now has proper path to the rtems git. README.gw contains a basic sequence of steps needed to compile the gw, starting from compiling build tools, compiling rtems and then compiling gw.
Adding config file for rtems. Targets rtems4.10 from git.