Plugins now pump state and it works!

Plugins now pump state and it works!
We had to use an 'explicit' way of passing state back,
but it works quite nicely as seen by this test:

austin@continuum ~/c/h/infinity-0.4> ghci Infinity.hs
GHCi, version 6.8.2: http://www.haskell.org/ghc/  :? for help
Loading package base ... linking ... done.
...
*Infinity> x <- initplugins (enabledplugins config)
...
*Infinity> (s,_) <- runplugin undefined x "get" Nothing
"Nil"
*Infinity> (s,x') <- runplugin undefined x "put" (Just ["hello world"])
*Infinity> s
"Done"
*Infinity> (s,_) <- runplugin undefined x' "get" Nothing
"hello world"
*Infinity> saveplugins x'
*Infinity> ^DLeaving GHCi.
austin@continuum ~/c/h/infinity-0.4> ls State/
StateTest.st
austin@continuum ~/c/h/infinity-0.4> ghci Infinity.hs
GHCi, version 6.8.2: http://www.haskell.org/ghc/  :? for help
Loading package base ... linking ... done.
...
*Infinity> x <- initplugins (enabledplugins config)
...
*Infinity> (s,_) <- runplugin undefined x "get" Nothing
"hello world"
*Infinity> Leaving GHCi.
austin@continuum ~/c/h/infinity-0.4>

Very fun stuff, indeed. We can now go full force ahead
with the actual connection code!

(Note: we also removed the Core.hs-boot file as I noticed
it now has no purposes.)