Attached is a rough patch that tries to fix this problem.  I changed the behavior in that unicode char 0x2028 is no longer treated as a line separator.  It would be trival to change the regex to support that too, if we want to preserve backwards compatibility.  Personally, I think readlines() on a codecs reader should do that same line splitting as an 'io' file.

If we want to use the patch, the following must yet be done: write tests that check the splitting on FS, RS, and GS characters.  Write a news entry.  I didn't do any profiling to see what the performance effect of my change is so that should be checked too.