Port Zet to DE0_Nano board
Fix type in SCHEMATIC.txt

Tab/Space mismatch (I use tabstop 4)
Now boots DOS6.22 via console

Host console emulates a read-only 1.44MB floppy disk
Bugfix console restarting emulation

Prevent re-send of sector on restarting disk emulation (symptom: DOS
hangs with media descriptor error)
Corrected PS/2 connector pinout

It was wrong! Added a note about confusion.
Bugfix console sector transfer

Now works when requesting the same sector twice (no need for a request
counter, just used low byte of address)
Add DIP switches for configuration

Details in README
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