Rename all expression pieces to not mention Matlab explicitly.

Since all expressions are in fact general pupose expression, and not tied
to Matlab in the slightest, avoid calling the classes as Matlab*.  No actual
functional change is required for this.

git-svn-id: https://groke.mcmaster.ca/svn/grad/colin/branches/TableTool_javization@10848 57e6efec-57d4-0310-aeb1-a6c144bb1a8b