Switch to RecursiveDo pragma to remove warnings on GHC 7.6+

GHC 7.6 deprecates DoRec in favor of RecursiveDo. Switch to using
the preferred pragma. (This will cause a warning on 7.4, which
deprecated RecursiveDo in favor of DoRec. Not much to be done about
that.)

Also switch to 'mdo' from 'do rec'. In 7.4 both forms performed
segmentation; in 7.6, only mdo does. This probably doesn't matter
to our tiny recursive snippet, but segmentation is generally the
better default.
Fix layout typos
Merge pull request #462 from zopa/master

Switch to RecursiveDo pragma to remove warnings on GHC 7.6+
Allow :substitute use delimiters other than /
Make C-n completion use words from all open buffers instead of only current one.
add a script to re-install yi and yi-contrib. I do this enough to warrant a script ;-)
Merge remote-tracking branch 'origin/master' into vty-5.0
Merge remote-tracking branch 'upstream/vty-5.0'
Update upper alex version bound to 3.1.2.
Ask travis to build with GHC HEAD too.
Merge remote-tracking branch 'upstream/master'
More informative error from ghciLoadBuffer
Remove redundant Data.Binary import
Remove no longer necessary qualified name
Don't use LambdaCase to allow building with ≤7.6.1
Get rid of a trailing whitespace.

If this causes problems for anyone browsing git logs, ask git to not
show you whitespace-only changes.
Honour -y flag.

Perhaps we should warn the user if the directory chosen with -y doesn't
exist or doesn't house the config file.
Remove upper bound on alex version.
Merge pull request #464 from Fuuzetsu/ghciMsg

ghciLoadBuffer error message improvement
Merge pull request #466 from Fuuzetsu/whitespace

Get rid of a trailing whitespace.