describe system word size at start of tests
simplify memory allocation
store system variables inside memory map

included fixing a few tests which were assuming input buffer starts at 0
isolated dependency on "bytes" ready for moving to absoluet addresses
moved system "constants" into the memory map
moved constants to come before variables, just for prettiness
now uses real memory addresses.
moved test diagnostics to a separate module
inlined "natural" into "number"
removing cruft
more cleanups - removed real_address
number tidyups
cleaned up momory mapping a bit
build both 32-bit and 64-bit versions with standalone boot for x86
moved memory model out of language code and into startup/test
a bit more memory twiddling
removed the need for sys_consts and sys_vars pointers
a bit of annotation in assembler start code
annoying modes - what does this?