Added warning/error parsing.
Updated error printing.

- Errors alternate in color
- Errors with newlines are now correctly parsed
Made knuth alternate bold and unbold colors.

The parsing of messages is still a bit screwy though, so errors aren't
being displayed super well.
Build now deleted output directory.

Before, moving directories into .knuth-out would fail if they already
existed. Now, we eliminate the possibility.
Fixed OUTPUT_DIR bug.

Before, if .knuth-out didn't exist and we tried to delete it, a warning
was printed. Now, the warning isn't printed.
Added lol and toc to sanitize
Merge pull request #10 from mwhittaker/knuth-errors

knuth error update