Canvas should be 101x101

[gingerbeardman]

• I have no idea if the examples will also need to be changed

[dribnet]

Thanks Matt for this first version. My intuition is that this change would make the canvas 101 pixels wide, but by allowing x=101 and not x=0 as in the original implementation (and similarly for y) - but would be happy to be wrong on this if I'm reading it wrong. I would also double check other dbn commands which were meant to operate over the same range of 0 to 100 inclusive like pen and paper as those often had logic that tied directly to the canvas, such as can be found in the dbn introduction

Paper 0
Pen 100
Repeat A 0 100
{
  Pen A
  Line A 0 A 100
}

[dribnet]

Here's a useful unit test for this change.

// symmetric canvas test
Paper 20
Pen 100
Line 0 0 0 100
Line 50 0 50 100
Line 100 0 100 100

Current result:

Expected result: