Merge pull request #2 from luite/master

Make it work with GHC HEAD
Bump version to 0.6.0.1 (fixing compatibility with ghc-7.8).
Progress in Embedded C version: snapshotWith partially done.
More hold and snapshotWith.
Add quaternary lift in C++ implementation.
Code tidy-up and a script to run the memory tests.
Note that memory-test-7 currently fails. That's the next job.
Add some more (currently failing) memory tests, and do some tidy-up.
Fixes to some test cases.
Fix memory leak shown in memory-test-8.hs and memory-test-8a.hs.
Fix markup in changelog
Merge pull request #3 from pxqr/patch-1

Fix markup in changelog
A note about memory management added to the README file.
Dep can be 'newtype', not 'data'.
Add split primitive to Haskell.
Tiny comment tweak in sodium.cabal
Fix ambiguity in poodle.hs
Comment tweak in split.
Add executeAsyncIO and executeSyncIO primitives.
Let's have -O2 on by default. Why not?
Improve comments for execute*IO.