Course import tool should import text descriptions of sections

The import tool successfully imports activities from one course into the appropriate week or topic of another course. However, it ignores text content in the donor week or topic and does not import that into the new week or topic. There is no warning that this content is not going to be imported, and the fact that the import tool is aware of weeks and topics means it should be able to copy text or description content as well. The import tool should be improved so it is more consistent as to the content it can handle.