Introducing <@> and <@@> functions

Function <@> is infix variant of between and <@@> is its flipped
counterpart. Documentation was updated to use these (mostly) in place of
between, but that's not all that was updated. Hopefully documentation is
now more comprehensive and readable.
GHC rewrite rules for function between

If one or both of the first two arguments of between are id (identity
function) then its definition can be simplified.

To check if these rules are firing we used ghc-core
(http://hackage.haskell.org/package/ghc-core,
http://www.haskellforall.com/2012/10/hello-core.html).
Explicit import of definitions from Prelude

Found some discussion about the possibility that NoImplicitPrelude might
be made default in one of the future definitions of Haskell and I kind
of like the idea.
Introducing <$@> and <@@$> functions

Convenience wrappers that combine fmap and <@> or <@@> respectively.
Both are useful for lens-like definitions.