Forgot to tell git to ignore the pdf.
Bound the base to [2, 36] for integer input/output.
Use correct value for 'true' flag (-1 as an unsigned integer)
In 2-cell integers, the most significant part is on top of the stack
Reading the spec, marking the places I am unsure about
Split the global array into various regions (partially done)

This commit adds the description of the various regions into
which we split the global array. So far, the change is only
implemented for the data space and data stack.
Testfile was wrongly using UNLOOP instead of LEAVE.
Implement return stack as part of the array.
New environment variables, since the stack sizes are now fixed
Store input string in input buffer (piece by piece).

This is only the first step: the next is to make the
address of the input buffer available using SOURCE.
Introduce short-hand for parsing a space-delimied word.
Add |SOURCE| word.

Reading the description of |EVALUATE| I realize that I may have to
alter how I handle the input buffer.  I will need to put the bounds
'min', 'parsed' and 'end' into array cells, because the programs
are allowed to access them.  Only 'parsed' is meant to be altered.
Fix 2/ for negative numbers.  Improve some overflow/underflow behaviour.
Bit operations (and, or, xor, invert, lshift, rshift).
Make display, and <, =, > use signed ints, add M*, UM*, S>D words.
Allow negative numbers to be input as -123.
Add U< and U. words, which act on unsigned numbers
Add FM/MOD, SM/REM, UM/MOD
Add pictured numeric output, and fixed a bug in the input buffer.

The code to refill the input buffer interacted badly with code
to fetch characters for words.  Also, there was an off-by-one
error in there.

The pictured numeric output involves <#, #, #S, SIGN, #>.
Add /HOLD environment variable.