[foreign-memaccess] RFR 8234644: Misc cleanup of the memory access API implementation

[Maurizio Cimadamore]

Hi,
now that the API javadoc is mostly in shape, I wanted to do a pass over 
the implementation, to make sure that classes have at least some minimal 
documentation, and that methods inside the impl classes are organized in 
a meaningful way (this should help the review process a bit).

Webrev:

http://cr.openjdk.java.net/~mcimadamore/panama/8234644/

Cheers
Maurizio