Add the necessary pieces to request the right type out of a binary expression.

Since binary expressions can actually change the type (for instance, comparisions
switch the type for the number input to boolean), handle this so calls further
up the chain don't break (for instance, boolean operators, ex AND).

git-svn-id: https://groke.mcmaster.ca/svn/grad/colin/branches/TableTool_javization@10471 57e6efec-57d4-0310-aeb1-a6c144bb1a8b