Created a new representation based on one monad instead of two. Implemented summarizeable class of monads for this purpose. Separate writer and reader monads caused problems when tried to implement references that are explicitely closed after use.
fixed some bad types, need to go for polymorphism
Fixed some of the instances. Polymorphism may not be available in this form, because of the partial nature of updates.
added unsafe operators (polymorphic use of partial lenses and traversals), created tests in Examples/Examples.hs
small fixes
some hints in comments

indexed traversals should be a specially defined version of a reference, with a -> (i,a)
added the possibility to close references
Merge branch 'one-monad' of https://github.com/lazac/references into one-monad
some renaming and refactoring, the semantics of monadic actions in setters and updaters
created a whole new branch with two controlling monads, but based on the experiences from one-monad based design
Merge branch 'operator-controlled' of https://github.com/lazac/references into operator-controlled

Conflicts:
	Control/Reference/Operators.hs
	Control/Reference/Predefined.hs
	Control/Reference/Representation.hs
created a working version for the two-monad operator-controlled