Written from VE!

Otherwise, when editing a file with VE, we would constantly write
to disk, which is a bit inefficient.

This gives us backspace handling. Also, remove all usages of C<
which allows us to remove the C<* override.

It's a quite useful word and it doesn't make sense to reload it from
disk after each usage.

This is the first commit I do entirely in VE. It's a habit I'm planning
on taking as it helps a lot to find usability issues.

When reaching the end of the buffer when typing in IBUF or FBUF, stop
typing instead of overflowing.

There wasn't much of a reason to leave a loop early on 0x0d or null.
The idea was that once you have a CR or null, the rest is garbage
and you shouldn't see it.

However, it brought a problem: In VE, you couldn't insert characters
past that limit. It would be written, but never displayed. So let's
get rid of this logic and simply always display a 64x16 grid.

It simplifies things. Also, removed ';' which became useless.

This allows cut&paste similar to VI's

Make F search from curpos+1 so that it's possible to search the
same word we've just found a second time. Previously, it would find
the word under the cursor.

Also, improve docs a bit.

Previously, it would keep the old buffer displayed why typing over
it. I had kept it thus because I didn't want to erase the buffer
right away because the behavior is that when we type nothing, we
keep the buffer as-is and repeat the action.

Now, the behavior of I and F is much better. It keeps the buffer
displayed until the first non-return keystroke and then erases it.

Also, fixed PSP leak in _type and fixed PSP overuse in successful
_F (they balanced out).

This fixes weird glitches I had on trs80. It's *always* a matter of
RAM initialization. By now, I should know...

Also, I've run VE on the TRS-80 for the first time! It doesn't work
well though. Screen is mostly blank all the time.

I removed instructions from the recipe which became obsolete when
Collapse OS became 100% bootstrapped. Also, I've updated instructions
to change the NL override which is necessary for blkup to work.

Kinda proud of this one. Efficiently piggy-backing on the Block
Editor, keeping things simple, and yet, building power into the
editor.

Which are end-of-word movements.

The indicator is going to be empty most of the time and will be
emitted by the mode changer directly. That's going to the upper-right
corner and the status bar avoids emitting in that area.

Also, add insert and find buffers to the header, making it 3 lines
high.

Also, fix the "I" overshadowing word which wasn't operating on the
proper RSP level.

Also, fix I which didn't mark the block as dirty.

Also, add MODE indirection.

not needed

The address returned in the error condition would be off by one.

I'm not sure why I chose null-terminated initially. Probably because
the z80asm version had null-terminated strings.

Length-prefixes strings are the traditional form of strings in Forth
and it's a bit easier to work with them with traditional forth words
when they're under this form.

I'm planning a string reform and it's standing in the way.

Now that everything is cross-compiled, no need to XPACK. If we ever
need it again, we know where to find it.

Now that the boot binary is fully cross-compiled, there's no use for
the linker anymore. Theoretically, it could still be useful, but I
can't think of a real use case.

Let's take it out of the picture. If it's ever needed again, I'll
know where to find it.

I'm planning on going back to 8-bit branching. 16-bit br cells incur
a non-negligible penalty and, while at first 64 words (128 bytes
forward or backward) seemed a bit limiting, I now don't see why one
would ever construct such a big branch. It would be un-forthy.

Also, I looked at using BC instead of IY to hold IP and the transition
would be a lot easier with 8-bit branching.

In this commit, all I do is add overflow checks in IF. The mechanic
below doesn't change. I'll give myself some time to think it over so
that I avoid yet another back and forth.

Prebiously, when encountering an error during a : ; definition from
input buffer, because the input buffer wasn't flushed, we would continue
interpreting and quit the whole program when encountering ;.

Use EXX instead of the stack for HL protection and remove all
spurious uses of chkPS,

I wanted to inline chkPS in next because of its "tight loop" status,
but for reasons I don't understand, doing so breaks Collapse OS.
Later...