Unify coding style

@sjaeckel integrated clang-format with formal coding style. Run his
script and commit changes.

There are pros and cons of this commit.

Mixed coding style is a "broken window". A good single style simplifies
reading and writing code.

On the other hand, this is a big change which will lead to conflicts.

src/md5.h

@@ -21,7 +21,8 @@ struct MD5Context {
 };
 
 void MD5Init(struct MD5Context *context);
-void MD5Update(struct MD5Context *context, unsigned char const *buf,
+void MD5Update(struct MD5Context *context,
+               unsigned char const *buf,
                uint32_t len);
 void MD5Final(unsigned char digest[16], struct MD5Context *context);