Implement DiffPrettyHtml
Fix typo in doc
Wrote breaking test for BisectSplit_.
Switched DiffBisect and diffBisectSplit_ to use []rune instead of string.
When strings were used, invalid UTF-8 sequences were created.
Merge pull request #9 from zberg/master

Add DiffPrettyHtml
Merge pull request #12 from goojba/utf8bug

Use []rune in diff internals