Initial tokenline integration.

This implements only the show command.
Add sd mount/umount/ls commands.
Add sd cd command.
Use sd cd command.
Clean up cmd_sd_cd.
Add "sd cat" and "sd hd" commands.
Remove microrl (except for hydranfc build).
Add "sd erase" command.
Add "sd test-perf" command.
Update tokenline from remote repository.
Adjust to tokenline API update.
Add "sd pwd" command.
Update tokenline from remote repository.
Adjust to tokenline TARG/T_ARG change.
Add copyright messages.
Update tokenline from remote repository.
Convert mode framework to tokenline, and convert SPI mode.
Drop unneeded console feature.
Update tokenline from remote repository.
Fix up Apache 2.0 license headers.