/** View or edit a file with the default viewer or editor.
* \param filename file to open (encoded in utf8)
* \param mode open in VIEW or EDIT mode
* \returns whether or not the file is viewed (or edited) successfully.
*/
/** View or edit a file with the default viewer or editor.
* \param filename file to open (encoded in utf8)
* \param mode open in VIEW or EDIT mode
* \returns whether or not the file is viewed (or edited) successfully.
*/