Merge pull request #28 from mikedewar/master

stores; new blocks; tests
cleaning store
reverting StateLocker to Store
renaming
comments & org
error handling
changing manifest pair to make more sense
block test
more tests
make delay pass on my machine
adding null stream test
removing defer from Input
adding First and internalstate
Merge pull request #29 from nikhan/master

store and block improvements, added first and several benchmarks, introducing internalState