Fix.
make instance take a tmenv rather than a whole sig

since it ignores the tyenv. arguably the same should be done for
termsem.
make termsem take a tmenv rather than a whole sig
Generate asm output, needs disassembly
Added disassembly of generated x86
Moved defs into cakeml computelib, removed test case
some updates to the top-level README
delete the old compiler proof scripts
Changed pretty printing of letnone
move dbterm stuff to later in the file

I thought about getting rid of it since it's equivalent to something
purely in terms of db. But that's probably not worth the effort.
remove unnecessary side condition on new_type_definition
delete commented out stuff about no_functions
delete prompt_to_i3_special

it wasn't doing anything important beyond decs_to_i3, so just use that
directly. advantage of not pushing an unnecessary NONE constructor after
a known successful declaration.
delete obsolete reference to printerTheory

however x64_heap still fails about halfway through because of other
changes to printing that have happened
delete references to prompt_to_i3_special from bootstrap
Merge branch 'master' into Word8Array

Conflicts:
	compiler/proofs/compilerProofScript.sml
	explorer/pp/allPP.sml
	explorer/pp/astPP.sml

Conflicts in astPP.sml have not been touched.
The rest were resolved.
Overwrite changes in Word8 explorer with master
parameterise prog_to_bytecode over the instruction length

use real_inst_length for the compiler explorer and for prog_to_x86_64,
otherwise use \x. 0.
commented out broken bits of x64_heap...
move termination proof for inf_type_to_string earlier

unfortunately it still fails to go through the translator for some
reason