SWFUpload Class: Validate and process files uploaded with SWFUpload

This class can validate and process files uploaded with SWFUpload.

It takes the name of form input used to upload a file and validates the upload to check if the file it was uploaded without errors, checks if the file size is below the accepted limit, check if the file name has an extension from the list of accepted extensions, check if the file name length is below the accepted limit after cleaning any unacceptable characters, and checks if a file with the same was not already uploaded before.

The class can move the uploaded file to a given directory after creating its directory structure if it did not exist already.