Filtering of arrow keys in TTY-driver

[venomix666]

This PR adds filtering of the arrow keys in the TTY drivers of the Oric, PET and nano6502. The Atari does not need the filtering as the translation is done in the SCREEN driver.

I tried to also add filtering to the BBC Micro, but there is seems like the MOS moves the cursor when pressing the arrow keys and I didn't find a simple way to prevent that.

[venomix666]

Same problem with getroms.sh here as for Ivop's latest PR, seems like archive.org is down.

[ivop]

Looks like archive.org got hit by a DDOS and was hacked via a javascript library vulnerability. Usernames and salted passwords were stolen. News is they'll be back in days, not weeks.

[davidgiven]

I'll assume this works --- merging. Thanks!

Re the BBC Micro: this is actually a bit more complicated than it looks due to MOS' built in line editor. When doing normal editing, the cursor keys move a secondary cursor; pressing COPY will then copy whatever the secondary cursor is looking at into the buffer. But, when not line editing it would be desirable to make them produce normal keycodes. In order to support that the SCREEN driver would have to have a couple of extra entrypoints for start_line_editing and end_line_editing, but I'm not convinced they're worth adding just for the BBC Micro.