RBTree: Pure haskell Red-Black-Tree implemetation

Pure haskell implementation from Wu Xingbo (wuxb45@gmail.com) 2011

WARNING:This Implementation mainly concerns about functionality. 
  After that I will improve the performence and efficiency.

to Build & Install for yourself:
shell> runhaskell Setup.lhs configure --user
shell> runhaskell Setup.lhs build
shell> runhaskell Setup.lhs install

on any problem, you may try this:
shell> runhaskell Setup.lhs register

for system, replace '--user' with '--ghc'

changelog (0.0.2):
add bangpatterns to some data field.
add ghc optimization flags to .cabal
be careful of memory usage. insert 10MiB Int values takes 3 seconds and 800MiB memory space.

changelog (0.0.3):
add function "searchFast".
rename 'remove*' functions to 'delete*'s.

changelog (0.0.4):
add functions for search min/max value.
add functions for search for a interval that the two values in the tree holds the given value
modified search functions can accept a 'compare' function like:
    (b -> a -> Ordering)
  search for an 'a' by first key of a (RBTree (a,b)) canbe done in such way:
> b :: Int
> b = 10
> t :: RBTree (Int,String)
> t = insertOrdList emptyRB [(1,"hello"), (2,"world")]
> result :: (Int,String)
> result = search (\k (k',_) -> k `compare` k') t 2
it returns "Just (2,"world")"

changelog (0.0.5):
add three operators for insert/delete/search.
updates the comments to co-op with haddock.
delete the RBTreeTest module. clean is better.