315 csv wrapper

Issue #315 - This works fine, but I feel that it might be better to not expose the file mode, and let the underlying ClCsv class handle it all. This is because it is very sensitive to which mode it is in.

For example, for updating a column in the CSV (see b_test_write_02), it *must* use mode ```'r+b'```, because it first needs to read the current data, then write to the file. It just may not be clear as could be desired which mode should be chosen. In fact, ```'r+b'``` should be used in almost all cases since anything with ```w``` in it will erase the current data in the file.