Made the CBM stdin consoles echo '\n' to the screen.

That fix makes Commodore platforms be consistent with other platforms' consoles.
Avoided a reload by using a second register.
Added a simplistic read() that gives a stdin console on the Atmos.
Moved the command-line arguments out of BASIC's input buffer.

The stdin console re-uses that buffer.
Reset the stdin console when a program starts.
Merge pull request #68 from greg-king5/line

Add a stdin console to the Atmos target.
Merge pull request #67 from greg-king5/echo

CBM stdin Console RETURN-key Echo
Merge remote-tracking branch 'upstream/master'