parser never returns

This is a primitve csv parser which skips intermediate blank lines:

``` haskell
parser :: Stream s m Char => ParsecT s u m [[String]]
parser = line `sepEndBy` (some endOfLine) <* eof
where line = many (noneOf ",\n\r") `sepBy` char ','
```

and looks like it works:

``` haskell
\> parse parser "" "1,2,3\n\n\n4,5,6"
Right [["1","2","3"],["4","5","6"]]
```

but if i change `some` to `many`:

``` haskell
parser :: Stream s m Char => ParsecT s u m [[String]]
parser = line `sepEndBy` (many endOfLine) <* eof
where line = many (noneOf ",\n\r") `sepBy` char ','
```

it will never return:

``` haskell
\> parse parser "" "1,2,3\n\n\n4,5,6"
^CInterrupted.
```

Reproduce the hang with the two parser definitions and the input shown in the issue. Start by tracing how sepEndBy combines line with many endOfLine, then compare that behavior with some endOfLine. Done means the parser terminates and its handling of intermediate blank lines is covered by a verified result.

Written by the indexing model from the issue text.