First cut at adding composite UPDATE column value support for INTs only.

Eg now you can use a more complex SET clause for a column like...
UPDATE table SET col1 = id + 8 - col2;

Previously (and currently with all column types other than INT), you had to select a constant value or a single column.
UPDATE table SET col1 = 5;
UPDATE table set col1 = id;

See added CompositeColumnValueModifier and changes to WhereProcessor, BaseSerializer (see addRawToStringRepresentation and addRawToRaw), and then IntSerializer for one implementation.

I reserve the right to backpedal on method and class names.  Some of those are getting painfully long here.

Not horribly well tested yet.  I'm also probably going to take a while to update the rest of the col types, since my immediate need is just INTs.  Happy to field pull requests.  ;^)