hlearn-cv.lhs: Space after > and before code sample.

According to the samples displayed on:

http://www.haskell.org/haskellwiki/Literate_programming

It is required to leave a space after a > and before the code. This repairs Github's presentation of the file as well.

Best wishes!
Update hlearn-cv.lhs: Space after > even in blank lines
Merge pull request #28 from asperous/patch-1

hlearn-cv.lhs: Space after > and before code sample.