This method calls the appropriate methods and external program to undertake the convertion of the
video to convert under a 3gpp conversion specifications.
Method to export the current library to a XML file at the location and with the name selected by the user.
This method opens a JFileChooser so the user can select where he wants to save the library and what he wants to call it.
Filename is checked for validity and corrected, once valid the export library method is called which will write the values to file.