parsers fails with attoparsec-0.12

```shell
Preprocessing library parsers-0.11.0.2...

[1 of 8] Compiling Text.Parser.Token.Highlight ( src/Text/Parser/Token/Highlight.hs, dist/build/Text/Parser/Token/Highlight.o )

[2 of 8] Compiling Text.Parser.Permutation ( src/Text/Parser/Permutation.hs, dist/build/Text/Parser/Permutation.o )

[3 of 8] Compiling Text.Parser.Combinators ( src/Text/Parser/Combinators.hs, dist/build/Text/Parser/Combinators.o )

src/Text/Parser/Combinators.hs:376:10:

Not in scope: type constructor or class `Att.Chunk'

src/Text/Parser/Combinators.hs:382:21:

Not in scope: `Att.endOfInput'
```

bug: https://github.com/ekmett/parsers/issues/39
Merge pull request #331 from Heather/patch-1

parsers fails with attoparsec-0.12