Merge pull request #11 from tLewisII/master

Extra Dictionary extensions + Thrush associativity
removed comment
added initial capacities
added Optional.getOrElse
use type inference for json examples
Added unsound functor stub
memory leak fixed
json prim instances
Added MVar
fixed mvar write
added a function
added user json decode example
added User json example to readme
added productivity helpers
updated json example
json example formatting
added some more productivity functions
added Either
Renamed type params on Either
renamed mvar's read to take