In the beginning of Collapse OS' Forth version, the readline sub-
system was optional. This is why we had this separate RDLN$ routine
and that the input buffer was allocated at boot time.

It's been a while since the RDLN system has been made mandatory, but
we still paid the complexity tax of this separation. Not anymore.

... and rename it to KEY?. Then, add KEY from KEY? for its blocking
version.

I need this for an upcoming Remote Shell feature. If a Collapse OS
system remotely controls another shell, it needs to be able to poll
both the remote system and the local keyboard at the same time. A
blocking KEY is incompatible with this.

In some places, the polling mechanism doesn't make sense, so this
new KEY? always returns a character. In some places, I just haven't
implemented the mechanism yet, so I kept the old blocking code and
added a "always 1" flag as a temporary shim.

I have probably broken something, but in emulators, Collapse OS runs
fine. It's an important reminder of what will be lost with the new
"dogfooding" approach (see recent mailing list message): without
emulators, it's much harder to to sweeping changes like this without
breaking stuff.

It's fine, I don't expect many more of these core changes to the
system. It's nearly feature-complete.

Splitting a word into MSB/LSB pairs happens often and is worth, I
think, native words. Also, I'm going to need it in the upcoming
commits.

Recipes contain bits and pieces of hardware-related knowledge, but
these bits feel sparse. I've been wanting to consolidate hardware-
related documentation for a while, but always fell at odds with the
recipes organisation.

We don't have recipes anymore, just a /doc/hw section that contains
hardware-related documentation which often translate to precise
instructions to run Collapse OS on a specific machine.

With this new organisation, I hope to end up with a better, more
solid documentation.

With KEY and EMIT being switch words, most of the high layer can
be defined before drivers.

In addition to this change, I've compacted core blocks which were
becoming quite sparse.

The idea is to consider assemblers as "runtime" apps instead of
placing them in the "bootstrap" section of the blocks. These apps
will be used for much more than bootstrapping.

Moved its documentation to doc/asm.txt and made its code blocks
more compact.

It's more descriptive this way. Also, I'll soon add a new HERESTART
config.

Previously, recipes that began spitting binary contents before
loading block 282 would end up with VARIABLE code in their binary,
thus breaking them. We fix this by making this loading process
2-part.

ref #82

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.

and renamed it "Core words". Also, reworded the presentation.

Instead of letting each configuration taking care of RDLN$ and
"CollapseOS" prompt, move this to BOOT to simplify xcomp units.

Initialization source code is now only for driver initialization.

During "make updatebootstrap", we use less than 0x20 bytes on the
PSP side and less than 0x40 bytes on the RSP one. 0x100 bytes ought
to be enough for anybody.