Fix EmptyLinesAroundBody so it doesn't report blank lines.

This resolves a conflict ("clobbering") between `EmptyLinesAroundBody` and `TrailingWhitespace`. An extra blank line containing whitespace would cause them to try to remove the same characters in `--auto-correct`. The solution is to divide the offences between them. `EmptyLinesAroundBody` doesn't report offences for lines containing spaces now.