(keving)

Big Bang introduction of CPR Analysis Pass.  Note that now
-fstrictness only does the strictness analysis phase,  it is necessary
to follow this with -fworker-wrapper to actually do the required Core
transformations. The -O option in the ghc driver script has been
modified appropriately.

For now,  CPR analysis is turned off.  To try it,  insert a
-fcpr_analyse between the -fstrictness and the -fworker-wrapper
options.

Misc. comments:

- The worker flag has been removed from an ID's StrictnessInfo field.
Now the worker info is an extra field in the Id's prag info.

- We do a nested CPR analysis,  but worker-wrapper only looks at the
info for the outermost constructor,  else laziness can be lost.

- Id's CPR Info in traces and interfaces file follows __M

- Worker-wrappery transformation now accounts for both strictness and
CPR analysis results.