Bug: Imported exercise rung fields containing spaces

It was possible by using quoted fields to import a native mode CSV file whose exercise rung field included embedded spaces. This would cause a native database file to be written which, when {\tt monthlog::load} attempted to load it, would cause the parser to abort. I added code to {\tt monthlog::importCSV} to delete any spaces in an exercise rung field.

To cope with existing database entries with spaces in exercise rung fields, I added code to {\tt monthlog::load} to delete all spaces from the record. An entire database can be cleaned up by performing a trend recalculation. (Reported by Tom Gunter.)