Rename smtlibgenerator to smtlibchecker.

To stay at least a little consistent, use smtlibchecker for the smtlib
package name.

git-svn-id: https://groke.mcmaster.ca/svn/grad/colin/branches/TableTool_javization@10660 57e6efec-57d4-0310-aeb1-a6c144bb1a8b