AW: Cleaning up include file inconsistencies

[Dr. Matthias St. Pierre]

> > Me, I'm wondering if it wouldn't be clearer if we renamed
> > crypto/include/internal -> crypto/include/crypto, and thereby did
> > this:
> >
> >     #include "crypto/evp.h"
> >
> > That, to me, is much clearer than the "_int" suffix.
> 
> This sounds like an excellent idea to me.

Wouldn't it even be better to move 

   `crypto/include/internal`  to  `include/internal/crypto`

and include it as

    #include "internal/crypto/evp.h"

this would have the advantage that _all_ shared include files can
be found in the `include` folder, the public ones inside `include/openssl`
and the internal ones in `include/internal`. Also, it would be a very consistent
structure and easy to remember.

    #include "internal/foo.h"                  /* shared between libcrypto and libssl */
    #include "internal/crypto/bar.h"     /* shared by libcrypto modules only */
    #include "internal/ssl/bar.h"            /* shared by libssl modules only */

   ... and so on: ...
   #include "internal/engines/baz.h"   /* shared by engine modules */

Matthias