File Release Notes and Changelog

Finally, a new release of batteries, with support for OCaml 3.12, a new testing infrastructure with tests auto-extracted from source and using QuickCheck for property verification, new useful functions and modules, documentation improvements and lots of bug fixes.

New functions:
* Array.modify, modifyi added to modify arrays in place
* Set.subset added to test for subset relationship
* Int.compare improved for speed
* Path.normalize improved features
* Bigint.to/of_float added
* Random.full_range added
* Map.modify, modify_def to modify a map value in-place
* Substring.length
and many more

New modules: BatHeap, BatUref, BatDeque, BatHashcons
Auto-detection of camomile version at compile time