The SHA4 name was not clear with regards to the new SHA-3 standard. So
SHA2 and SHA4 have been renamed to better represent what they are:
SHA256 and SHA512 modules.
More fixes based on the compiler directives -Wcast-qual -Wwrite-strings
-Wmissing-prototypes -Wmissing-declarations. Not everything with regards
to -Wcast-qual has been fixed as some have unwanted consequences for the
rest of the code.
process functions
Access to process functions is needed to reduce possible timing attacks
on SSL MAC checks. As SSL is set to move to using the dynamic MD layer,
the MD layer needs access to these process functions as well.
