Corrections of issues and help improvement

Hi,

I've made an update of my previous patch, which resolves some bugs I found on this forum and complete the help to explain the import process. Now, you can import child, description, weight, synonym and related terms without reported problems.

So before an official release, here is the update. Remove the extension .txt of the filename and replace the original file in module.

Sincerely,

Daniel Berthereau