Support sugared ops in type0 instructions

This resolves a problem latent since d8fae90.
Improve robustness of dogfooding

Use $(SILENCE) in dogfood rule
Add hardware simulation to `make check`

Run Icarus simulations of qsort and bsearch demos in `make check`. Factor the
`make check` rule and order it more sensibly. Suppress directory change
notification (needed for check rules, but apparently needs to be a global
setting).
Removing trap and throw support

Remove EIB

Simplify and mend halt states

Renumber states
Stabler reset behaviour

Change DCM_SP to DCM_CLKGEN. In the process, reset behaviour improved
stability : `make burn` with reset held down now comes out of reset
properly, and bouncing on reset does not have obvious unpredictable
results.
Cosmetics
Excise the unused debugger
Documentation for type3
Assembly for type3
Disassembly for type3

Update outdated field names and tags

Move some defines to ops.h

Generalise instruction bitfields
Simulation for type3

No more `illegal` ; now if `P == 0xffffffff` we halt.
Hardware for type3
Testcase for type3

Update the `toolong` testcase as well.
Documentation for pack
Assembly / disassembly for pack
Hardware for pack
Simulation for pack
Testcase for pack

This test case tests all operations in multiple contexts.
Remove obsolete `valid` flag
Improve Makefile cleanliness and behaviour