ANN: Shake v0.15

[Neil Mitchell]

Hi,

I'm pleased to announce Shake v0.15. I had hoped to go straight from
0.14 to 1.0, but there is enough still changing that I'll need a 0.15
series. The highlights/things to watch out for are:

* A few bugs fixed with using digests, in particular it could
sometimes build either too much or not enough. If you are using
digests you should definitely upgrade. Thanks to Luke Hoersten for
finding these issues.

* The cmd function has been completely rewritten. It's now faster at
capturing output (10x or so), and polymorphic so you can capture
either String, ByteString or Lazy ByteString. Because return types
like Stdout are polymorphic there may be instances where you need a
type signature. That's only likely to happen if you weren't using the
output at all, in which case instead of Stdout _ use Stdout () and as
an added bonus it will use less memory and go faster too.

* The shakeFiles option used to be joined to your files with <.>, but
now it uses </>, so if you had shakeFiles=".shake" then previously
files ended up in .shake.database, whereas now they end up in
.shake/.shake.database. It was a common mistake to forget the trailing
/ to shakeFiles, so it's now automatic.

* I am now signing the git tags with GPG. I don't really know what I'm
doing, but I can see the fingerprint in gitk, although not GitHub.

The Shake 0.15 release was delayed about 2 weeks due to Shake
discovering a GHC 7.10 RC3 bug, the story of which is written up here:
http://neilmitchell.blogspot.co.uk/2015/03/finding-ghc-bug.html

Thanks, Neil