Clear data directory

This is a utility command that clears out the data subdirectory /data under Digital Atmosphere. Normally it does not need to be used unless suspicious plots or contours occur and the user wishes to flush out all data.

This ensures that File > does not inadvertantly retrieve files that were placed there by the user. It can also prepare the data directory in case the user wishes to place numerous files into the directory to be imported.

Data that has already been imported and stored in native binary format will remain unaffected, but "Import directory" will not work at all until new data is placed in the data directory (via a file copy or via the Internet > command).