vchoi_fork

[svn-r13884] The second step of optimization for compound data for the Chicago
company.  The I/O is optimized when the source and destination 
members are a subset of each other one way or another, and
the order is the same, and no conversion is needed.  For example:
    struct source {            struct destination {
        TYPE1 A;      -->          TYPE1 A;
        TYPE2 B;      -->          TYPE2 B;
        TYPE3 C;      -->          TYPE3 C;
    };                             TYPE4 D;
                                   TYPE5 E;
                               };
    or
    struct destination {       struct source {
        TYPE1 A;      -->          TYPE1 A;
        TYPE2 B;      -->          TYPE2 B;
        TYPE3 C;      -->          TYPE3 C;
    };                             TYPE4 D;
                                   TYPE5 E;
                                };
The optimization is simply moving data from the source to the 
appropriate places in the buffer and bypass the reading of 
the background data and data conversion.

Tested on smirom, liberty, sol, and copper.