[DOCS] C code documentation

[Michael Scott]

PDD 7 "Conventions and Guidelines for Parrot Source Code" has a section 
on "Code Comments" that has been followed for C code. I'm about to 
change this.

The existing documentation headers will be replaced with pod headers 
contained within C multi-line comment delimiters. I'm going to stick to 
exactly the same style that I used in the Perl scripts. Functions will 
be proceeded with similarly formatted descriptions. No information will 
be lost.

Perhaps the most controversial feature of all this is that I'm using 
rows of 80 '#'s as visual delimiters to distinguish documentation 
sections from code. This may seem like overkill to some. I'm basing it 
on what looks right to me in BBEdit and Xcode. If it turns out that it 
doesn't work for everyone, I'll change it.

If anyone feels strongly about this then speak.

Mike