babel-haskell: variety of bug fixes

babel-haskell: variety of bug fixes

  Thanks to Christopher Witte for raising these issues

* lisp/babel/langs/ob-haskell.el (org-babel-expand-body:haskell):
  replaced missing () wrapping, and now using correct variable
  expansion

  (org-babel-execute:haskell): now using
  org-babel-haskell-initiate-session to start sessions

  (org-babel-haskell-initiate-session): only starting sessions if none
  exists, also added a .25 second wait on brand new sessions to allow
  the Haskell interpreter to fire up

  (org-babel-load-session:haskell): now optionally accepts processed
  params to avoid over-execution of variable resolution

  (org-babel-prep-session:haskell):  now optionally accepts processed
  params to avoid over-execution of variable resolution, also placing
  the variable definitions directly in the session instead of loading
  them from a separate file