Nuke include/Typeable.h, create include/containers.h instead.

The "Typeable.h" collides with the header of same name in base.

The new "containers.h" is now used in every Haskell source.
It contains more stuff used across the containers codebase:
- INSTANCE_TYPEABLE[0-2] (was in Typeable.h)
- include MachDeps on __GLASGOW_HASKELL__ to define WORD_SIZE_IN_BITS
- define STRICT_x_OF_y macros
- define MIN_VERSION_base if not defined by cabal (during cabal-less build)