Add nonWhitespaceSequence scope type

[pokey]

We can call it "paint", and it will expand to include all non-whitespace characters adjacent to selection. Can proceed by:

1. Get line containing end of selection
2. Move end forward until just before the first whitespace character you encounter
3. Get line containing start of selection
4. Move start back until just after the first whitespace character you encounter

Question: what to do if one of the endpoints is in the middle of whitespace? Which of the following do we do:

• Leave the endpoint untouched
• Move it forward until the end of the next non-whitespace block
• Move it backward to the end of the preceding non-whitespace block