Infinite loop when first word is longer than line

[ef4]

It's possible to trigger an infinite loop if the first words in a string are too long for the line. We end up trying to use @spaceLeft before it's initialized, which then causes us to break off too big a piece of the word, which causes @spaceLeft to go negative, which makes this loop run forever:

while w > @spaceLeft
  w = @wordWidth word.slice(0, --l)

To see the bug try running:

doc.text("COMPRESSION STOCKINGS KNEE-HIGH", {width: 64});

[devongovett]

Looks like #305. Thanks for the fix.