Merge pull request #13 from Gabriel439/pipes-4.0

Added 'Base m ~ IO` constraint to the safe functions
Removed `()` argument from some pipes
Merge pull request #14 from Gabriel439/removeUnit

Removed `()` argument from some pipes
Fixed haddock code examples
Merge pull request #15 from Gabriel439/fixhaddocks

Fixed haddock code examples
Use `MonadIO` in `fromSocketN`
Updated the documentation to refer to pipes instead of proxies

This reflects the fact that the default `pipes` API and tutorial currently
de-emphasize the bidirectional features and users might be confused about
what 'Proxy' refers to.
Merge pull request #16 from Gabriel439/proxy2pipe

Updated the documentation to refer to pipes instead of proxies
Removed Pipes.Network.Internal module
Documentation markup
Cabal documentation