Fixes various warnings emitted in lib by the SunPRO cc compiler, and

Fixes various warnings emitted in lib by the SunPRO cc compiler, and
synchronized the MD5 prototypes with OpenSSL.

* MD5 operates on binary data, not characters. Avoid signed/unsigned issues
* The bswap16/32 macros was not signed/unsigned safe
* lib/rfc2617 had several spurious extra ;
* MD5Final wants an unsigned char *