Add Prelude.concat and Prelude.mapM benchmarks.

Change function supplied to Prelude.map.
Merge pull request #65 from archblob/benchmarks

Add Prelude.concat and Prelude.mapM benchmarks.
Updated documentation
Updated documentation
Merge branch 'master' of github.com:Gabriel439/Haskell-Pipes-Library
Migrated `run` to `Pipes.Prelude` and replaced it with `runEffect`

This was done for consistency with other monad transformers.  The old run
is still in `Pipes.Prelude` for people who find `runEffect` too verbose.
Fixed `README.md` to use `runEffect`
Moved `liftCatchError` source back to `Pipes.Lift`
Merge branch 'master' of github.com:Gabriel439/Haskell-Pipes-Library
Removed 'run' from `Pipes.Prelude`

This is based on a suggestion from @k0001 that it's better not to have a
redundant function in order to improve the readability of `pipes` code, so I
decided to pick `runEffect`.
Fixed some minor errors in the tutorial code examples
Added community-contributed libraries to the README
Polished tutorial
Changed 'toHandle' to not swallow broken pipe exceptions

This is in response to issue #71
Changed `run` to `runEffect` in `Pipes.Prelude` examples
Pipes.Prelude.stdout: be more precise when catching "broken pipe"
exceptions.

This change is discussed in issue #71
Merge pull request #76 from k0001/match-ePIPE

Pipes.Prelude.stdout: be more precise when catching "broken pipe" exceptions.
Polished source code
Added more folds to `Pipes.Prelude`
Generalized type of `toHandle`